In a retaining wall, these blocks are stacked together in several courses, and capped off with a concrete capstone at the top. The blocks are hollow, which makes them lightweight and easy enough ...

One of the largest domes in the world, the Pantheon, is made of concrete. You saved a lot of money building this dome with concrete. But remember: concrete is very heavy. About halfway down the ...

It will take a lot of iron chains and money to keep your heavy concrete dome from collapsing. Besides, there's an easier -- and less risky -- way to build a dome this tall today. Try again!