Floating house
Place a lot of columns aruond the ground and build your condominium on top of it. When you're done, delete all the columns. Note: Make sure you have a way to get to the house, or no one can get in. Also, you can build a conodminium up to ten stories high up. Make sure you put floor tiling on the top of the column so you can put a second column on top of it.
