Ulduar

Ulduar is the massive Fortress capital of the Thunderlands of Valhalla, and the seat of the Titan Odin the only Titan who makes his home on Earth. Ulduar contains the portal which leads to the Noble Titans fortress of Olympas within the Fade, which makes the fortress of extreme importance.

Inside, Ulduar is a profusion of tunnels and stairs and balconies. The entire place appears to be carved out of a massive cave, and many of the levels are natural ledges. It has the feeling, as if nature were improved upon rather than replaced or recreated. The surfaces are a strange mix of smooth and unaltered stone and ice, as when a master sculptor works in stone and lets the material’s natural texture add depth and beauty. It shows where the dwarves got their skill in stonework, but judging by Ulduar they're still a long way from matching their creators.