Bangladesh is a country within the South Asia. Hence , the Earth Explorer website under the United States Geological Survey (USGS) archives the Landsat imageries which span from 1972 till date.
Therefore, you can download the satellite imageries of Bangladesh from 1987 - 2020 (and NOT before 1972).
I have made a manual which details step-by-step guide to assessing the datasets from the Earth Explorer website (https://earthexplorer.usgs.gov).
Please see attached copy and follow the instructions provided in the manual . It would surely be of great use to you.