Both cities (Mohenjo-Daro and Harappa) are built in similar architectural style, and were generally not heavily fortified like other Indus Valley cities. There was some kind of administrative centrality between these two cities, but its extent remains unclear.
Other similarities include a grid system setting up the first city blocks and a running water system that provided water to each individual block. Both of the cities belong to the same civilization called Harappa civilization. They were both built around the 26 Century BC.