Answer – Beas
Description: Alexander, after gaining control of the former Achaemenid satrapy of Gandhara, including the city of Taxila, Alexander advanced into Punjab, where he engaged in battle against the regional king Porus, whom Alexander defeated in the Battle of the Hydaspes in 326 BC.
Thereafter, Alexander’s marched east put him in confrontation with the Nanda Empire of Magadha and the Gangaridai of Bengal. As per documents, the Nanda army was supposedly five times larger than the Macedonian army.
Alexander’s army was exhausted, homesick, and anxious by the prospects of having to further face large Indian armies throughout the Indo-Gangetic Plain, mutinied at the Hyphasis (modern Beas River) and refused to march further east. Alexander, after a meeting with his officer, Coenus, and after hearing about the lament of his soldiers, eventually relented, being convinced that it was better to return. Alexander, then erected huge altars as a mark of his invasion of India. With the time those altars faded and completely demolished.