Sanhedrin Tombs in Wikipedia

The elaborate Sanhedria Tombs lie to the north of the city.[9] They were so called by later generations because the largest of them contains 70 chambers with burial benches, and the Sanhedrin had seventy member.[9] Each of the three tombs would actually have contained the burials of a single, multi- generational, wealthy family. They were constructed between the reign of Herod and the year 70.[9]

Link: https://en.wikipedia.org/wiki/Tomb_of_the_Sanhedrin#Second_Temple_era_tombs