3D terrain already works without a key, using open elevation data. A free Cesium ion token adds Cesium World Terrain: more detailed mountains and smooth sunlight on the slopes.
Create a free account at ion.cesium.com/signup and copy the default token from your dashboard — about a minute.
Stored only in this browser.
Every frame waits until the map tiles are sharp, so the video is smooth even if your computer is not.
Drag the map to change the angle and scroll to zoom while a follow camera is active. “Free” leaves the camera to you.
Map attribution is always added in small print, as the tile providers require.