Petra

Petra lies at the crossroads of trade routes from India to Egypt and southern Arabia to Syria.

An excerpt from the article 26 facts about Petra
The location made Petra an important communication and commercial hub in the region. The Nabataeans supplied the caravans with water and other necessary travel supplies, conducted trade, and collected merchant fees for services and passage. The city's safe location among the rocks was also an important factor for further city development.