Many burial caves were found in the Sanhedrin caves. The whole area is part of the necropolis, a very big, underground cemetery used during the Second Temple period in Jerusalem. There are a few reasons why this area in Jerusalem has so many burial caves. First, the area was used for stone quarrying - taking huge pieces of stone out of the ground to use them to build things. This left large caves. Also, at the time, rich people in Jerusalem liked the idea of burial caves. This made the idea of a necropolis easier and popular. 