Odds are, you've built a sandcastle before. Maybe you decked it out with elaborate turrets. You may have even dug yourself a killer moat. Though your sandcastle was probably pretty awesome, it may have paled in comparison to the sandcastles of Calvin Seibert.
Seibert just returned from a trip to Hawaii, where he utilized the pristine sand beaches to create a series of futuristic sandcastles. His designs are geometric and precise, so much so that it's hard to believe these are only made from sand. Don't feel bad about your crumbling castle - Seibert spent the last 30 years working as a sculptor's assistant, so he has some serious skills. Check out his visionary sandcastles below.