The title pretty much explains itself, I felt like listing all of the places I am aware of and have been to. Feel free to comment if I don't know a certain place! [No, users maps don't count. xD ]
Places I know and have been to:
Lonely Cave
Ficho Tunnel
Bonfire Island
South Pole
Atlantis
Last Cave
Flourite Plains
Cape of Distant Worlds
Ascension Island
Sky's Rim
Temple of Dreams
Wow...that list seemed longer in my head. xD