I always thought the concept of urban beaches was a bit depressing. I remember back in Birmingham, every Summer a cheap flight company would dump a ton of sand next to a fountain in the middle of one of the squares and call it a 'beach'... as if we weren't the most landlocked city in the country, here's a reminder you are too cheap for even this lowcost airline. But as someone whos ambition is to visit every beach on Earth even our little rooftop beach makes me happy.
I used a wooden crate we were using as a veg box and a bucket of sand that my Xmas tree stood up in - just add toys and small children with inherited capacity for small pleasures (and by toys I mean little yellow diggers and mummy's vintage teaspoons!)
Add a little water to change the texture, bury toy dinosaurs and play 'paleontologists', sink your hands underneath the sand for a great sensory experience... I can't think of a more perfect childhood memory than playing in a sandbox.
And a little flag to make Sand-ringham Castle:
...and after the revolution...
...at least I make myself laugh, right?