Who broke down the walls of Jericho?" Biblical

The same person (and his tribesmen) who supposedly wrote the book of Joshua.

God did. The children of Israel stepped out in faith and God caused the walls to fall.

Some would say that angels did the work (Joshua 5:13)... but it was still the people stepping out in faith. Combined effort?

God caused it to happen, do you want name of Hewbrew leader, story of how it happened,

Yes, the Israelites marched around Jericho 7 times and then shouted and the walls crumbled. They did this out of obedience to the command given by God to Joshua. So we are never actually told the exact dynamics of HOW or WHAT caused them to crumble, but we do know that GOD did it.

Not sonic vibrations?

Just like with many Biblical miracles, God used natural phenomena to create what were miracles for those involved..

It was the result of being obedient to God

I like how hiccups is nowhere to be seen right now...

As Fr_Chuck mentioned... do they want the specifics of how it fell or the whole story of what went on? I wouldn't get too worked up over this post until the OP returns.