Joshua 7, 8 - Ai was the second city conquered by Joshua and the Israelites after entering the Promised Land. Their first attempt failed but they succeeded on their second attempt.
The location of Ai is controversial. The traditional site is at Et-Tell but there is no evidence of an ancient conquest. Consequently, others believe the true site is Khirbet El-Maqatir.
There are many videos supporting the Khirbet El-Maqatir site on the Associates For Biblical Research YouTube channel