Push-ups, also known as press-ups, are a staple of bodyweight training. Primarily targeting your pectoral muscles, when done properly it is a highly effective full body workout that also hits the back of your arms, core, and legs. It also has the added benefit of being able to be done anywhere without any equipment and is the safest chest exercise you can perform by yourself.
Often performed with poor form, quite a few weightlifters who are able to bench press very heavy loads struggle to be able to do a set of push-ups.