Pillar of Fire
Pillar of Fire is an Adventure Map location, where a visiting hero can see "Distant Lands", as the description states. It means, that everything within a 20 square radius is revealed for the player. Even areas clouded by a Cover of Darkness will be revealed, though they will be overclouded again at the beginning of the next day. Pillar of Fire is basically an underground version of the Redwood Observatory, though it can be used above ground as well. Additionally, Tower's Lookout Tower has a similar effect.