The Shaheed Minar (Bengali: শহীদমিনার ShohidMinar lit. “Martyr Monument”) is a national monument in Dhaka, Bangladesh, established to commemorate those killed during the Bengali Language Movement demonstrations of 1952 in then East Pakistan.

On 21 and 22 February 1952, students from Dhaka University and Dhaka Medical College and political activists were killed when the Pakistani police force opened fire on Bengali protesters who were demanding official status for their native tongue, Bengali.The massacre occurred near Dhaka Medical College and Ramna Park in Dhaka. A makeshift monument was erected on 23 February by students of University of Dhaka and other educational institutions, but soon demolished on 26 February by the Pakistani police force.

The Language Movement gained momentum, and after a long struggle, Bengali gained official status in Pakistan (with Urdu) in 1956. To commemorate the dead, the Shaheed Minar was designed and built by Bangladeshi sculptors Hamidur Rahman in collaboration with Novera Ahmed. Construction was delayed by martial law, but the monument was finally completed in 1963, and stood until the Bangladesh Liberation War in 1971, when it was demolished completely during Operation Searchlight. After Bangladesh gained independence later that year, it was rebuilt. It was expanded in 1983.

National, mourning, cultural and other activities held each year to mark 21 February, Ekushey or Shaheed Dibas (Martyrs’ Day), are centred on the Shaheed Minar. Since 2000, 21 February is also recognised as International Mother Language Day.

Reference- https://en.wikipedia.org/wiki/Shaheed_Minar,_Dhaka

External  source for more info- https://en.wikipedia.org/wiki/Shaheed_Minar,_Dhaka