User blog comment:SLyfoX999/WHITE GOLD TOWER IN SKYRIM!!!/@comment-4057437-20120726045207

We can confirm this, though we had to W.W.Sprint to the rooftop of the Smithy and then to the top of the building nexrt to it. We found a place where we could fall into the lake, then headed south. We tried to get to the tower, but fell through the terrain into water. We were able to swim right up to the tower, (which doesn't look like it did in Oblivion). When we got there, it dissappeared.

While we were in Cyrodil, we tried to conjure Avrak, but couldn't. (When were outside the purple barrier around the Soul Cairn, we could summons him and ride him.)  You can get outside the Soul Cairn by using the W.W.Sprint to get to the top of the wall that splits the Soul Cairn, then look for a spot to fall outside the barrier. There is no way back, so save first.

Anyway, we kept on swimming and the tower reappeared behind us. Unlike the outside the Soul Cairn, we were able to fast travel back to Skyrim.