Short answers, pulled from the story.
Charles Masson discovered the ruins of Harappa in 1829 while wandering through the Punjab region as a deserter from the East India Company's army. He made copious notes and illustrations of the site, which he erroneously dated to the time of Alexander the Great's campaigns.
The Indus Valley Civilisation thrived from 3300 BCE to 1300 BCE and spanned much of modern-day Pakistan, northwestern India, and northeast Afghanistan. Most cities were abandoned by around 1700 BCE following a gradual decline that began around 1900 BCE.
The cities of the Indus Valley Civilisation were located in modern-day Pakistan, northwestern India, and northeast Afghanistan. Major urban centres included Mohenjo-daro and Harappa, which are now UNESCO World Heritage Sites.
The Indus Valley Civilisation declined due to climate change that caused an abrupt and critical mega-drought and cooling 4,200 years ago. The Ghaggar-Hakra system was rain-fed and water-supply depended on the monsoons, which grew significantly cooler and drier from about 1800 BCE.
The people of the Indus Valley Civilisation achieved great accuracy in measuring length, mass, and time using a system of uniform weights and measures. The smallest division marked on an ivory scale found in Lothal in Gujarat was approximately 1.704 mm, and chert weights followed a ratio of 5:2:1 with each unit weighing approximately 28 grams.
The Harappan language is the unknown language of the Indus Valley Civilisation, and the Harappan script is yet undeciphered. Between 400 and as many as 600 distinct Indus symbols have been found on stamp seals, small tablets, and ceramic pots, but the messages are too short to be decoded by a computer.