Ganon's Tower

Ganon's Tower is a location found in multiple Legend of Zelda video games. It first appeared in The Legend of Zelda: A Link to the Past for the SNES where it appeared as the final dungeon of the entire game. In the game it was sealed shut with the only thing capable of breaking it being the decendants of the seven sages. The boss of the dungeon is the malevolent Agahnim.

The tower would later appear once again in The Legend of Zelda: Ocarina of Time and The Legend of Zelda: The Wind Waker. It should also be noted that similar towers have been featured in other Zelda titles as well, though weren't named so.

As you could assume, this is Ganon's, the main antagonist of the series, tower, just as the name suggests.