Update: STK World Terrain has been deprecated, see Introducing Cesium World Terrain
The STK World Terrain has incorporated the complete SRTM 30 meter resolution dataset published and managed by USGS, which covers most of the globe between 60 north and 60 south. No need to update your URLs; the data was updated on the servers over the weekend. You can browse the data here, or just simply open up your own favorite Cesium or STK application to stream in the terrain. Also, from a quality perspective, many of the minor terrain artifacts have been corrected from the raw SRTM data.
Mount Sinai, Egypt
Mount Ararat, Turkey