The city of Harappa was uncovered in 1921 and the city of Mohenjo-Daro was discovered a year later in 1922. These are believed to have been two major cities in this early civilization. It is unclear what the status of the cities were. Were they individual city-states or part of a larger kingdom? Each city was approximately one square mile in size and showed a very high level of planning and organization. The cities had well-organized perpendicular streets and buildings constructed out of uniform-sized bricks. They also consisted of drainage and sewage systems that would carry dirty water away from the city.