Admittedly, Seattle isn't exactly well-known for its luxurious sandy beaches. But that didn't prevent us from trying to build sandcastles back in our day. So we know exactly how difficult it is to get a bucket of sand to release perfectly into a building block for our castles, making these incredible sand castles by Calvin Seibert all the more impressive. We can hardly believe these geometrically precise castles are actually made of sand. Maybe we should dust off our sand castle equipment before the summer ends and see what we can whip up! To see more of Seibert's amazing sand castle architecture, click here.