According to the Bible and archaeological discoveries, the city of Jericho had a very thick wall. The Bible says that the wall was so thick that they could build a house on top of the wall.
When the Israelites came to Jericho they made camp some distance from the city walls. The Lord then told the Israelites that the next morning their warriors and seven priests should walk around the city once, and that all of them must be quiet except for the seven priests who had to blow on trumpets. The Israelites had to do that for six days, and on the seventh day they had to walk around the city seven times and on the seventh time they all had to shout. After that the walls fell inside out and the Israelites conquered the city