Kalibangan is the correct answer because it is the place where the archaeologists have discovered that not only the citadel but the lower town too was enclosed by a wall and fortified. Kalibangan is one of the prominent Indus Valley Civilization sites located in present-day Rajasthan, India. The excavations at Kalibangan have provided valuable insights into the urban planning, architecture, and lifestyle of the Indus Valley people.

Excavations at Kalibangan

- The excavations at Kalibangan were carried out by B.B. Lal in the early 1960s. The site was discovered in 1953 by Amlanand Ghosh.
- The excavations revealed the remains of a citadel and a lower town.
- The citadel was a raised platform made of mud-brick walls and was located on the western side of the site.
- The lower town was located to the east of the citadel and was also surrounded by a wall.

Wall and Fortifications

- The excavations at Kalibangan have revealed that both the citadel and the lower town were enclosed by a wall and fortified.
- The walls were made of mud bricks and were constructed in a systematic manner.
- The walls were thick and provided protection to the inhabitants of the city.
- The presence of fortifications indicates that the people of Kalibangan were concerned about the security of their city and took measures to defend it.

Significance of the Discovery

- The discovery of the fortified walls at Kalibangan provides evidence of the advanced urban planning and architecture of the Indus Valley Civilization.
- It suggests that the people of Kalibangan lived in a well-organized and structured society.
- The fortifications also indicate that the city was involved in trade and had interactions with other settlements in the region.
- The discovery of the fortified walls at Kalibangan adds to our understanding of the Indus Valley Civilization and its complex urban systems.

In conclusion, it has been revealed through excavations at Kalibangan that both the citadel and the lower town were enclosed by a wall and fortified. This discovery provides valuable insights into the urban planning and architecture of the Indus Valley Civilization.