Proof!

2 sides of the path leading to the ampitheater

The Ampitheater
*tah dah!*

If you look carefully, you'll see the remnants of a bridge.
This bridge represented the northern entrance to the settlement.
Obviously the stream below provided a great water source and, in addition to the hill on which Beit She'an is situated, good natural defenses.
*Over the hill is Jordan*

Those Romans, they sure did know how to build an arch.
But seriously, the place is covered in the them.
Wait....