Beach House

The beach house started when Ailise found a tiny sand island in the middle of the ocean/lake/river/whatever, thinking this would make a fine place for a tiny beach house. The idea evolved later to make it higher like a light house. The beach house kept growing and growing and then later K came along and it became a high tech HQ, with alot of hidden doorways, stairs way, the inside part (which there is no access to directly) is full with redstone circuits for all the devices.
Later it even became a portal station to other worlds in our multiverse and also the primary station of the monorail.