CesiumGS/cesium ? reverse-engineered prompt

I want to build a web application that's centered around an interactive 3D globe, a bit like a lightweight Google Earth. It needs to run directly in a web browser without any special plugins for the user to install.

The main thing is a high-quality, hardware-accelerated 3D globe that you can spin around, zoom into, and explore. It should be able to stream in different map layers, like satellite imagery and realistic 3D terrain, from various sources. A key feature I need is the ability to add my own custom data on top of the globe—things like 3D models of buildings, markers for specific locations, or even dynamic data that updates over time.

This should be built using a modern open-source JavaScript library. Make sure it's cross-platform and works smoothly on both desktop and mobile browsers.