There are lots of sources from which you can get this data.
You need to look at following links
Listed here are free sources for finding GIS data in both vector and raster formats including satellite imagery.
Some of the sources include
- Natural Earth World GIS Data
- OpenStreetMap Data
- Vector Map (VMap)
- USGS EarthExplorer
For your case
Natural Earth World GIS Data
This is probably one of the best sources for free global GIS data.
The site was initiated in 2008 by Nathaniel Vaughn Kelso and Tom Patterson and data from the site is coordinated by a group of volunteers.
Good for a global collection of free GIS data.
Individual layers can be downloaded from Natural Earth for cultural, physical, and raster data at three scales of resolution: 1:10m, 1:50m, and 1:110m. All of the GIS data offered at Natural Earth is public domain and free to use.