The two black circles are portals. The one with the crystals leads to South Pole. The other one leads to Ficho tunnels. From Ficho you can get to Flourite Plains and Bonfire. In Flourite there is an island where you can reach the Cape of Distant Worlds, where all the portals to any custom or downloaded maps can also be accessed. From South Pole you can get to Atlantis, and then Last cave. Ascention Island can be found in Lonely Cave, and from Ascention you can reach Sky Rim. ^^