The official Copernicus Data Space Ecosystem viewer. Free access to the full Sentinel archive with visualisation, comparison, timelapse and download tools.
tools / planet-explorer
Planet Explorer
Planet Labs' imagery platform, with near-daily 3-5 m PlanetScope coverage of the whole Earth and high-res SkySat tasking. Access is commercial, though research and NGO programs exist.
similar tools
Archive of every published version of Esri's World Imagery basemap since 2014. Compare high-resolution satellite snapshots side by side to see when local changes happened.
3D globe with high-resolution satellite imagery, 3D buildings and terrain. The desktop Pro version adds historical imagery, which you need for change-over-time analysis.
Browse free Sentinel-1/2/3/5P, Landsat and MODIS imagery by date. False-colour, NDVI and SAR visualisations, timelapses and comparison tools.
US Geological Survey portal for searching and downloading Landsat imagery back to 1972, declassified spy-satellite photos (CORONA), aerial photography and elevation data.
No-code proximity search over OpenStreetMap. Pick features you can see in an image (e.g. a park, a tram stop, a tower) and a distance, and it returns every place where they occur together.