I want to achieve a graphic solution for the globe like the one in this project:
I mean, I need only the vectors drawing the shapes of the continents, maybe the biggest rivers (as in the example), but something minimalist, no images of any kind.
You can achieve something similar by hosting the Natural Earth vector data in a GeoServer which you configure to expose via WMS. The Cesium code then looks something like this:
var viewer = new Cesium.Viewer(‘cesiumContainer’);