Ann's, Alchemist Tower.
Ann's ambitions to become an alchemist have led her to build this tower to serve as a open working space. The location, Magic Island, was chosen specifically because of its magical properties and for the power it radiates. It also was chosen because of its geographical location. An island makes for good alchemy practice space because it has open space, but is isolated to the rest of the Minecraft world as to not disturb the "peace" of others. It is not yet finished, but will eventually have a library for enchanting, a "forge" room for anvils and furnaces, and a brewing room for potions.
It was temporarily inhabited by Weltinator2 after he became Stick of Magic's apprentice. One day, while he was making a few potions, he realized that Matty12164 had entered the building. He showed him around, but was then annoyed by Matty12164's sloppy habits of leaving random junk in sterilized potion chests. He jokingly hit him in an attempt to get him to stop, but accidentally hit him with his sword instead of his fist. Matty then became enraged and began putting on armor and drawing weapons. Weltinator2 panicked and attacked him several more times, then after realizing he wasn't doing much damage, fled to his boat on Magic Island's shore. The rest of the story has nothing to do with the Tower, and so shall not be written here.
Weltinator2 recently returned from his great adventure, and found that Stick of Magic had done a great deal of building while he was gone. However, her chests were very disorganized, so he set about cleaning them up. He is currently still there, and plans to continue learning from Ann the Arts of Enchanting and Brewing, in his attempt to learn all aspects of magic, from ARS Magica to Xeno's Reliquary.