One of the most exciting things to find on an archaeological dig is a destruction layer. A city level destroyed by fire tends to produce rich finds. Valuable things are trapped under ash and debris just waiting to be found. We can usually subject burnt seeds, grain, olive pits, et al. to carbon-14 tests and get an approximate date for the destruction.
What does a destruction layer look like? We found one in my square at the ancient biblical city of Lachish. Here is a short video highlighting a newly-discovered destruction level.