The Nagarjuna Sagar Dam is not exactly located in Guntur, Andhra Pradesh. It is on the border of Palnadu district in Andhra Pradesh and Nalgonda district in Telangana, though it is a popular tourist destination for people in Guntur being just 146 kilometers away.
The dam itself is a masonry dam on the Krishna River. It's one of the tallest masonry dams in the world, standing at 124 meters tall and 1,450 meters long. Construction of the dam began in 1955 and wasn't completed until 1967. The dam provides irrigation water to several districts in both Andhra Pradesh and Telangana, as well as generates electricity.
The dam creates a large reservoir, the third-largest artificial lake in the world, with a gross storage capacity of 11.472 billion cubic meters. The reservoir is a popular spot for boating, and the Andhra Pradesh Tourism Development Corporation (APTDC) offers boat tours. There are also several islands in the reservoir, including Nagarjunakonda, which was once the capital of the Ikshavaku dynasty. The ruins of several Buddhist monuments can be found on the island.
The best time to visit the Nagarjuna Sagar Dam is during the monsoon season, from September to October. This is when the dam's gates are opened, and the water cascades down the face of the dam in a spectacular display. Thousands of tourists flock to the dam to see this sight.