The Nords liked nines. So their cosmology consists of nine worlds, or realms, most of them home to a different race of beings. The Norse universe is based around YGGDRASIL, the Tree of Life. This is the tree you need to talk to. Its branches support the different realms.
The exact nature of the NINE-WORLDS is a little hazy — no-one seems to have taken notes while traveling around it or measured it properly with GPS. There is uncertainty about which order the realms are in and even which way is up. However, the following list seems reasonable and is also compatible with modern Asatru which is always handy. Starting at the bottom, in the northern underworld, and heading upwards we have:
2: HELHEIM, the icy domain of the dead.
3: SVARTALFHEIM, the land of the dark elves (or dwarves).
4: JOTUNHEIM, land of the giants.
5: MIDGARD, Middle-earth, our bit, the realm of humans.
8: ALFHEIM, the land of the light elves.