Talk about a smart real estate investment: According to city records, the owner of this apartment, artist Abraham Lubelski, paid $500,000 for the place back in 2003. Now, it's on the market for $5.5 million, meaning he could make a staggering $5 million profit if it sells for its full ask. (It's done a fair bit of price jumping over the years—it was priced at $7.4 million in 2011, $3.3 million in 2013, and then $6.75 million again last year.) Granted, the space is pretty raw, and the listing even notes that "this residence provides a unique opportunity to bring your architect to overhaul and customize." There are five official bedrooms, and tons of other living spaces—a home office, two galleries, and a loft, along with two kitchens and several bathrooms. So basically, if you have money to spend and a big idea on how to transform a space, this could be the perfect place.