Drip sand castles are a fabulous beach activity for all ages. Just dig a hole in the sand until you reach water, then pick up some really wet sand out of the hole using your hand and drip it in a pile to create a castle. They look like amazing sandy stalagmites!
See how tall you can build one, or make one with lots of towers. I think they have a rather gothic look to them.
Check out some very cool, gravity defying drip castles by clicking here.