Seamless Shuttle Radar Topography Mission (SRTM) 30 Arc Second (~1km)
The SRTM tiles are DEM data divided in to one degree blocks for the surface of the earth. The data is divided into two resolutions, one at 3 arc seconds (90m) and one at 30 arc seconds (900m). 80% of the earths surface is covered for all of the area between 60 degrees N and 53 degrees S.