Okay kiddo, imagine you're at a big party and you want to play a game of tag with your friends. But there's a problem - the ground is hot and uncomfortable to walk on. So you ask someone to bring you a bucket of water to cool the ground down.
Well, the Pool of Siloam was kind of like that - except instead of cooling down a party game, it was a place where people went to wash themselves. Back then, people didn't have soap and clean water like we do now, so it was really important for them to have a place where they could clean themselves off.
The Pool of Siloam was a big, man-made pool that was built over 2,000 years ago in Jerusalem. It was near the city wall and the temple, which meant it was a really important place for people to go. In fact, it was so important that it was mentioned in the Bible!
People would come to the Pool of Siloam to wash themselves before they went into the temple to pray. And sometimes, if they were sick, they would even go into the pool to try to heal their bodies.
So, that's what the Pool of Siloam was - a big pool where people would go to wash themselves and make themselves clean before going to the temple. Pretty cool, huh?