Babylon was home to one of the most wondrous of the seven wonders by all accounts. which was it?

It was the Hanging Gardens of Babylon constructed under the order and rule of King Nebuchadnezzar II for his wife Queen Amytis. It was a remarkable structure and a feat of engineering in the ancient times but the ruins of such remarkable structure is still missing until now.

Hanging Gardens--one of the Seven Wonders of the ancient world.

The Hanging Gardens of Babylon have been described in many pieces of classical literature but their existence has not been verified beyond ancient text. The gardens have been described differently from large rooftop gardens to gardens hanging from balconies to gardens stretching up into the air. Historians believe the gardens were connected to the royal palace and were created by Babylonian royalty.

The answer is ethnic groups.

The congress completes the diagram