http://skyscraperpage.com/cities/?buildingID=114292
This site is home to a two-story parking garage, which makes it a wonderful location in downtown Minneapolis to build a skyscraper!
In that case, a challenge is needed.
Until January 1st of 2018, anyone can submit designs that fit into a 48x48x410 meter box and follow the (very lax) architectural guidelines noted in the link above.]
Maximum 2 designs per user (not counting designs drawn at different angles). At the end of the challenge, a vote will be held and whoever wins will get some form of bragging rights or something of that kind.
Good luck, and have fun!