eing an official account Archaeological Excavations at Mohenjo-daro carried out by the Government of India between the years 1927 and 1931. A two volume work by one of the key site excavators, with one volume of plates and diagrams, the other with text and descriptions and essays by A. S. Hemmy, B. S. Guha and P. C. Basu. It is an archaeological site in the province of Sindh, Pakistan. Built around 2500 BCE, it was one of the largest settlements of the ancient Indus Valley Civilisation, and one of the world's earliest major cities, contemporaneous with the civilizations of ancient Egypt, Mesopotamia, Minoan Crete, and Norte Chico. It was abandoned in the 19th century BCE as the Indus Valley Civilization declined, and the site was not rediscovered until the 1920s. Significant excavation has since been conducted at the site of the city, which was designated a UNESCO World Heritage Site in 1980. The site is currently threatened by erosion and improper restoration. It was built in the 26th century BCE. It was one of the largest cities of the ancient Indus Valley Civilization, also known as the Harappan Civilization, which developed around 3,000 BCE from the prehistoric Indus culture. At its height, the Indus Civilization spanned much of what is now Pakistan and North India, extending westwards to the Iranian border, south to Gujarat in India and northwards to an outpost in Bactria, with major urban centers at Harappa, Mohenjo-daro, Lothal, Kalibangan, Dholavira and Rakhigarhi. Mohenjo-daro was the most advanced city of its time, with remarkably sophisticated civil engineering and urban planning.