For the reviews who said these are flimsy . Technically its cheaper because of shipping costs on Lego. and they've been used for all manner of creations. Not sure how they would turn out. I had a ton of Legos as a kid (who didn't. He is not the easiest to please . Much cheaper than buying a couple of tables for our boys. I'd recommend attaching them to a board (I wood-glued 6 of them to a board. They would be an even better investment over these baseplates. For those reviewers who said this thin base wasn't the same as what was on the market growing up. you really can't do without these baseplates if your child is going to build anything with legos. Great for building small sets. kids love them and they are a necessity for any lego builder. I found these plates a LOT cheaper in my local meijer's store. but are pretty sure that we will upgrade to a larger model for each of them soon. I've not had one broken on me yet. I was a bit disappointed with the quidditch practice LEGO set so I decided to buy this green baseplate and to buy two of the quidditch practice sets to make the ultimate quidditch pitch. These plates measure 10" by 10" (or 32 studs by 32 studs). My daughter and I have found the 15X15" baseplate a better size to make our structures on. He or she might find out that even ten by ten inches (25 cm per side) is not quite enough. It worked great for that. While of course kids will still leave the occasional lego lying around using the plates means it happens less frequently. and structure of the solid matter of a celestial body. but at least they're sturdy and you can connect them with Lego blocks to build bigger scenes. This is a comment in response to the review from the "Toy Enthusiast in Belmont"; perhaps he should become a little less enthused about toys and more enthused about the english language. They are too thin to support even a small structure. These are the floor for anything they want to construct using Leggo bricks. BUT - they are not the typical Lego quality. This was just what I needed. The plates measure 10 1/32 x 10 1/32 each. This lego building plate is a must have item. It's a bunch of fun anyway. This review is amended as of November 20. guled them on and the kids LOVE IT. Not too much to say-- it's a Lego building plate. When I was growing up the base boards were twice this size. but as it is a present for a kid who only knows the crappy quality of today - I am hoping she likes it - but the smaller one that she already owns. This is a good piece but not great. It's not the biggest plate