One of the finest choices is Landsat imagery from earthexplorer.usgs.gov. Here it’s available for different periods of imageries which we can use environmental changes and deduction.
In my previous thread I forgot to mention the oldest image dataset available (to 50 years back in time and with one optical broadband (Panchromatic photographs from a spy plane). Most of the imagery was taken above the former USSR and the PR of China, but at that time the US considered Iran as a rogue state, so there might be imagery available form Iran. Have a look at the follwoing URL to check and download imagery from the Corona spy lmmission (airborne data of very high resolution
URL: https://lta.cr.usgs.gov/declass_1
See also the following paper to process the Corona imagery:: https://www.researchgate.net/publication/235959317_Diachronic_mapping_of_LUCC_in_the_northwest_of_China_over_the_last_half_century_conversion_of_CORONA_Panchromatic_reflectance_into_LANDSAT_NDVI_imagery
Best personal regards,
Frank
Article Diachronic mapping of LUCC in the northwest of China over th...