S - Stygian Penal Colony - Hades Universe.
Tooting my own horn, the game shouldn't be limited to the third rock from the sun.
T - Tethys, a moon of Saturn
[/link]U - Underside of the Earth's crust
W for Washington DC
Looking for these : x100
H - Hörnersburg (I may have it misspelled, a fading memory this is. Also a Lego model.)