We see bleachers in parks, stadiums and other places that may need seats for people. The bleachers are usually made of wood and sometimes endure the sun, rain or any weather. They can be wet from the rain and hot from the sun but are still there when people need them. The only problem is that the wood becoming weak because of age. There are other bleachers that are made of cement and some places have aluminum bleachers which are easier to clean and also easy to move or transport.