Harappa and Mohenjodaro are the two major sites of the Indus Valley Civilization. These ancient cities were part of one of the world's earliest urban civilizations, flourishing around 2500 to 1900 BCE in what is now modern-day Pakistan and northwest India. The Indus Valley Civilization is known for its advanced urban planning, sophisticated drainage systems, and extensive trade networks.

1. Harappa:
- Location: Harappa is situated in present-day Punjab, Pakistan, along the banks of the Ravi River.
- Excavation: The site was discovered in the 1920s by archaeologists and extensively excavated in the following decades.
- Layout: Harappa was a well-planned city with a grid-like pattern of streets and buildings. It covered an area of about 150 hectares and had fortified walls.
- Structures: The city contained large public buildings, including a granary, a Great Bath, and a citadel. The Great Bath is a significant structure consisting of a large rectangular tank made of bricks, possibly used for religious or ritualistic purposes.
- Artifacts: Numerous artifacts were uncovered at Harappa, including pottery, seals, jewelry, and figurines. The seals were particularly important, featuring intricate carvings and inscriptions that are yet to be fully deciphered.

2. Mohenjodaro:
- Location: Mohenjodaro is located in the Larkana District of Sindh, Pakistan, near the Indus River.
- Excavation: The site was discovered in the 1920s and excavations were carried out between 1922 and 1931.
- Layout: Mohenjodaro was also a well-planned city, covering an area of about 250 hectares. It had a complex system of streets, lanes, and buildings.
- Structures: The city had a citadel on a raised platform, which likely served as a political or religious center. Various residential and commercial buildings were found, along with a Great Bath similar to the one at Harappa.
- Artifacts: Like Harappa, Mohenjodaro yielded a wealth of artifacts, including pottery, jewelry, tools, and toys. The famous "Dancing Girl" bronze statue and the "Priest-King" statue were discovered at this site.

Both Harappa and Mohenjodaro displayed remarkable urban planning, advanced architecture, and a relatively egalitarian society. The Indus Valley Civilization was characterized by its sophisticated agricultural practices, extensive trade networks, and a writing system that is yet to be fully deciphered. These two sites provide valuable insights into the ancient civilization that thrived in the Indus Valley thousands of years ago.