Pick a spot by the shoreline and make a gigantic pile of sand. Use your hands, or grab a spade or shovel to speed it along.
As water drains out of sand, the tiny grains nestle together, forming a cement-like mix; that’s why wet sand near the ocean holds together better than dry sand farther up the beach. So you want to fill your mountain with water. How to? Make a volcano! Dig out a crater at the top, then slowly pour in water with a bucket or cup—it will drain through the sand. Pour until it stops draining, then jump on it to really pack it in. (Whee!)
Now that you’ve got a foundation, use Wierenga’s pancake method to make towers: Take a super-wet scoop of sand and slap it down. Jiggle it a little to help the water drain. Then repeat until you’ve got a nice, tall—and lumpy—tower.
Once you’ve made the rough framework, shape it up, Wierenga says. Starting from the top, use an offset spatula or a plastic knife to form rooflines and to smooth out your towers and walls. Use a paintbrush to sweep off loose sand as you go.
Contrast on the surface of your castle takes it to the next level. “Varied textures reflect light differently to make features stand out,” notes Wierenga. Use whatever you’ve got nearby to add details to your creation: A plastic fork with tines removed will make cool ridges, an old pen or toothpick comes in handy to draw on bricks, and topping the castle with found objects like shells and seaweed will give it a truly unique feel. Grab a spoon to scoop out arched doorways, and use its handle to dig skinny windows. Now sit back, relax, and bask in the oohs and aahs!