It looks kind of like a lake or a large structure. Maybe it's just an opening with stone, dirt, or clay as the ground. Do you know?
If I remember correctly, that was a tower where the bell is situated.
When the bell in the middle of the village square rang to signal noon, everyone would take a break for lunch time.
And no, that's not a lake. That's just a large open area with no structures in it apart from the bell.