diff --git a/.gitignore b/.gitignore
index ff08a24..9f3fd21 100644
--- a/.gitignore
+++ b/.gitignore
@@ -33,6 +33,7 @@ erl_crash.dump
 
 # Ignore assets that are produced by build tools.
 /priv/static/assets/
+/priv/static/chunks/
 /priv/static/*.js
 /priv/static/*.html
 /priv/static/*.css
diff --git a/lib/mound_hunters_web/router.ex b/lib/mound_hunters_web/router.ex
index 424cf33..8eea294 100644
--- a/lib/mound_hunters_web/router.ex
+++ b/lib/mound_hunters_web/router.ex
@@ -65,7 +65,7 @@ defmodule MoundHuntersWeb.Router do
     if File.exists?(index_path) do
       conn
       |> put_resp_header("content-type", "text/html; charset=utf-8")
-      |> put_resp_header("cache-control", "no-cache")
+      |> put_resp_header("cache-control", "no-cache, must-revalidate")
       |> send_file(200, index_path)
     else
       send_resp(conn, 404, "Not found")
diff --git a/ui/src/components/AboutModal.vue b/ui/src/components/AboutModal.vue
new file mode 100644
index 0000000..0d9e6a6
--- /dev/null
+++ b/ui/src/components/AboutModal.vue
@@ -0,0 +1,358 @@
+<template>
+  <Teleport to="body">
+    <Transition name="modal">
+      <div v-if="isOpen" class="modal-backdrop" @click="closeModal">
+        <div class="modal-content" @click.stop>
+          <button class="close-button" @click="closeModal" aria-label="Close">
+            ×
+          </button>
+          
+          <div class="modal-body">
+            <h2>About This Project</h2>
+            
+            <section class="intro">
+              <p>
+                Around 2,000 years ago, the Hopewell culture built a 60-mile ceremonial road 
+                connecting Newark to Chillicothe, Ohio. Most of it has been destroyed by farming, 
+                but tiny remnants might still be hiding in the landscape—parallel earthen walls 
+                just 50cm tall, visible only as subtle shadows in the right light.
+              </p>
+              <p>
+                There's way too much terrain for archaeologists to analyze alone. That's where 
+                you come in! This tool lets you explore high-resolution lidar data and help 
+                search for lost sections of the Great Hopewell Road.
+              </p>
+            </section>
+
+            <section class="video-section">
+              <h3>Learn More About the Road</h3>
+              <div class="video-container">
+                <iframe
+                  src="https://www.youtube.com/embed/Ltu2hJwqId8"
+                  title="The Great Hopewell Road"
+                  frameborder="0"
+                  allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture"
+                  allowfullscreen
+                ></iframe>
+              </div>
+            </section>
+
+            <section class="instructions">
+              <h3>How to Use This Tool</h3>
+              
+              <p>
+                <strong>Start exploring:</strong> Check out the known archaeological sites on the map. 
+                Click the pin icon next to each site name to fly there and see the crisp lidar imagery. 
+                Click on any of the pins on the map to learn more about the cite, and follow up on 
+                the cited references to dive further down the rabbit hole.
+                Use the sidebar controls to customize what you see.
+              </p>
+
+              <p>
+                <strong>Hunt for the road:</strong> Right-click anywhere on the map (within Ohio) to 
+                request a tile. If someone's already requested it, you can load the interactive data 
+                instantly. Otherwise, you'll wait a bit for the processing pipeline.
+              </p>
+
+              <p>
+                <strong>Adjust the lighting:</strong> Once a tile loads, the shading sandbox opens. 
+                Change the lighting direction and exaggerate the terrain to increase contrast—this 
+                makes subtle features pop out. Click "Render Tile" to add it to the map.
+              </p>
+
+              <p>
+                <strong>Mark your finds:</strong> Found something interesting? Drop a pin using the 
+                geometry tools in the top right. Then share it on 
+                <a href="http://discord.gg/miniminuteclan" target="_blank" rel="noopener noreferrer">
+                  Discord
+                </a> 
+                with coordinates and a screenshot!
+              </p>
+            </section>
+
+            <section class="about-author">
+              <h3>About me</h3>
+              <p>
+                I'm Mark Kalsbeek, a web developer and researcher from the Netherlands. 
+                I was inspired to build this after watching Milo's video above. If you want to 
+                reach me, @ me on
+                <a href="http://discord.gg/miniminuteclan" target="_blank" rel="noopener noreferrer">
+                  Milo's Discord
+                </a>: 
+                <span v-if="!usernameRevealed" class="username-reveal" @click="revealUsername">
+                 reveal
+                </span>
+                <span v-else class="username">{{ username }}</span>
+              </p>
+            </section>
+
+            <section class="thanks">
+              <h3>Thanks</h3>
+              <p>
+                Special thanks to <a href="https://gis1.oit.ohio.gov/geodatadownload/" target="_blank" rel="noopener noreferrer">Ohio OGRIP</a> 
+                for making high-quality lidar data freely available with an easy-to-reverse API.
+              </p>
+              <p>
+                Map tiles from <a href="https://www.openstreetmap.org/" target="_blank" rel="noopener noreferrer">OpenStreetMap</a> contributors 
+                and satellite imagery from <a href="https://www.esri.com/" target="_blank" rel="noopener noreferrer">Esri</a>.
+              </p>
+              <p class="tech-stack">
+                Built with: Elixir (plug_cowboy, jason, geo, logger_file_backend, httpoison, mime), 
+                Python (laspy, scipy, numpy, pyproj), 
+                Deno (Vue, Vite, Three.js, MapLibre GL, Pinia),
+                and of course Claude for infinite amounts of grunt work.
+              </p>
+            </section>
+          </div>
+        </div>
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<script setup>
+import { ref, watch, onMounted } from 'vue';
+
+const MODAL_VERSION = '1.0';
+const STORAGE_KEY = 'aboutModalVersion';
+const OBFUSCATED_USERNAME = '404d61726b6b313136';
+
+const isOpen = ref(false);
+const usernameRevealed = ref(false);
+const username = ref('');
+const seenRecentVersion = ref(true);
+
+const emit = defineEmits(['update:modelValue']);
+
+const props = defineProps({
+  modelValue: {
+    type: Boolean,
+    default: false
+  }
+});
+
+const revealUsername = () => {
+  username.value = OBFUSCATED_USERNAME.match(/.{2}/g)
+    .map(hex => String.fromCharCode(parseInt(hex, 16)))
+    .join('');
+  usernameRevealed.value = true;
+};
+
+watch(() => props.modelValue, (newVal) => {
+  isOpen.value = newVal;
+});
+
+watch(isOpen, (newVal) => {
+  emit('update:modelValue', newVal);
+  if (!newVal) {
+    // Mark as seen when closed
+    localStorage.setItem(STORAGE_KEY, MODAL_VERSION);
+    seenRecentVersion.value = true;
+  }
+});
+
+const closeModal = () => {
+  isOpen.value = false;
+};
+
+// Check if should show on mount
+onMounted(() => {
+  const seenVersion = localStorage.getItem(STORAGE_KEY);
+  if (seenVersion !== MODAL_VERSION) {
+    seenRecentVersion.value = false;
+  }
+});
+
+// Expose methods for parent component
+defineExpose({
+  open: () => { isOpen.value = true; },
+  seenRecentVersion,
+  close: closeModal
+});
+</script>
+
+<style scoped>
+.modal-backdrop {
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100vw;
+  height: 100vh;
+  background: rgba(0, 0, 0, 0.7);
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  z-index: 1000;
+  padding: 1rem;
+}
+
+.modal-content {
+  position: relative;
+  background: white;
+  border-radius: 8px;
+  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
+  max-width: 60vw;
+  max-height: 80vh;
+  width: 100%;
+  overflow-y: auto;
+}
+
+@media (max-width: 768px) {
+  .modal-content {
+    max-width: 95vw;
+    max-height: 90vh;
+  }
+}
+
+.close-button {
+  position: absolute;
+  top: 1rem;
+  right: 1rem;
+  background: none;
+  border: none;
+  font-size: 2rem;
+  line-height: 1;
+  cursor: pointer;
+  color: #666;
+  padding: 0;
+  width: 2rem;
+  height: 2rem;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: color 0.2s;
+  z-index: 1;
+}
+
+.close-button:hover {
+  color: #000;
+}
+
+.modal-body {
+  padding: 2rem;
+  padding-top: 3rem;
+}
+
+h2 {
+  margin-top: 0;
+  margin-bottom: 1.5rem;
+  font-size: 1.8rem;
+  color: #333;
+}
+
+h3 {
+  margin-top: 2rem;
+  margin-bottom: 1rem;
+  font-size: 1.3rem;
+  color: #444;
+}
+
+section {
+  margin-bottom: 2rem;
+}
+
+section:last-child {
+  margin-bottom: 0;
+}
+
+p {
+  line-height: 1.6;
+  color: #555;
+  margin-bottom: 1rem;
+}
+
+p:last-child {
+  margin-bottom: 0;
+}
+
+.intro p:first-child {
+  margin-bottom: 1rem;
+}
+
+.video-section {
+  margin: 2rem 0;
+}
+
+.video-container {
+  position: relative;
+  width: 100%;
+  padding-bottom: 56.25%; /* 16:9 aspect ratio */
+  margin: 1rem 0;
+  background: #000;
+  border-radius: 4px;
+  overflow: hidden;
+}
+
+.video-container iframe {
+  position: absolute;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+}
+
+.instructions p {
+  margin-bottom: 1.2rem;
+}
+
+.instructions strong {
+  color: #333;
+}
+
+a {
+  color: #0066cc;
+  text-decoration: none;
+}
+
+a:hover {
+  text-decoration: underline;
+}
+
+.username-reveal {
+  display: inline-block;
+  background: #333;
+  color: white;
+  padding: 0.1rem 0.5rem;
+  border-radius: 3px;
+  cursor: pointer;
+  font-size: 0.9rem;
+  user-select: none;
+}
+
+.username-reveal:hover {
+  background: #444;
+}
+
+.username {
+  font-family: monospace;
+  color: #333;
+  font-weight: 500;
+}
+
+.tech-stack {
+  font-size: 0.85rem;
+  color: #666;
+  line-height: 1.5;
+}
+
+/* Modal transitions */
+.modal-enter-active,
+.modal-leave-active {
+  transition: opacity 0.3s ease;
+}
+
+.modal-enter-from,
+.modal-leave-to {
+  opacity: 0;
+}
+
+.modal-enter-active .modal-content,
+.modal-leave-active .modal-content {
+  transition: transform 0.3s ease;
+}
+
+.modal-enter-from .modal-content,
+.modal-leave-to .modal-content {
+  transform: scale(0.9);
+}
+</style>
\ No newline at end of file
diff --git a/ui/src/components/MapControls.vue b/ui/src/components/MapControls.vue
index a346b8b..e0b7c55 100644
--- a/ui/src/components/MapControls.vue
+++ b/ui/src/components/MapControls.vue
@@ -1,5 +1,13 @@
 <template>
   <div class="layer-controls">
+   <button 
+     class="about-button" 
+     :class="{ 'pulse-highlight': !aboutRef?.seenRecentVersion }"
+     @click="aboutRef.open"
+     >
+      About this App
+    </button>
+    <AboutModal ref="aboutRef"/>
     <!-- ============================================= -->
     <!-- BASE MAP SELECTION -->
     <!-- ============================================= -->
@@ -110,7 +118,9 @@
 </template>
 
 <script setup>
+import { ref } from 'vue';
 import { KNOWN_SITES } from '../data/historicSites.js';
+import AboutModal from './AboutModal.vue';
 
 // ============================================================================
 // INTERFACE
@@ -155,6 +165,8 @@ defineProps({
   }
 });
 
+const aboutRef = ref(null);
+
 defineEmits([
   'update:baseLayer',
   'update:historicMarkersExpanded',
@@ -194,6 +206,42 @@ const sites = KNOWN_SITES;
   font-size: 14px;
 }
 
+/* ============================================= */
+/* About button */
+/* ============================================= */
+
+.about-button {
+  padding: 6px 14px;
+  border-radius: 6px;
+  border: none;
+  color: #fff;
+  background: linear-gradient(180deg, #4B91F7 0%, #367AF6 100%);
+   background-origin: border-box;
+  box-shadow: 0px 0.5px 1.5px rgba(54, 122, 246, 0.25), inset 0px 0.8px 0px -0.25px rgba(255, 255, 255, 0.2);
+  user-select: none;
+  -webkit-user-select: none;
+  touch-action: manipulation;
+}
+
+.about-button:focus {
+  box-shadow: inset 0px 0.8px 0px -0.25px rgba(255, 255, 255, 0.2), 0px 0.5px 1.5px rgba(54, 122, 246, 0.25), 0px 0px 0px 3.5px rgba(58, 108, 217, 0.5);
+  outline: 0;
+}
+
+@keyframes pulse {
+  0%, 100% {
+    box-shadow: 0 0 0 0 rgba(59, 130, 246, 0.7);
+  }
+  50% {
+    box-shadow: 0 0 0 20px rgba(59, 130, 246, 0);
+  }
+}
+
+.pulse-highlight {
+  animation: pulse 2s infinite;
+  position: relative;
+}
+
 /* ============================================= */
 /* CONTROL SECTIONS */
 /* ============================================= */
diff --git a/ui/vite.config.js b/ui/vite.config.js
index 08160bf..54fdf55 100644
--- a/ui/vite.config.js
+++ b/ui/vite.config.js
@@ -20,9 +20,14 @@ export default defineConfig({
         main: resolve(__dirname, 'index.html'),
       },
       output: {
-        entryFileNames: 'app.js',
-        chunkFileNames: 'chunks/[name].js',
-        assetFileNames: 'assets/[name].[ext]'
+        entryFileNames: 'app-[hash].js',
+        chunkFileNames: 'chunks/[name]-[hash].js',
+        assetFileNames: 'assets/[name]-[hash].[ext]',
+        manualChunks: {
+          'vendor': ['vue', 'pinia'],
+          'three': ['three'],
+          'maplibre': ['maplibre-gl']
+        }
       }
     }
   },