Wikimapia is an online editable map - you can describe any place on Earth.
Or just surf the map discovering tonns of already marked places. http://www.tangopolix.com/adserver/www/delivery/ck.php?ct=1&oaparams=2__bannerid=28__zoneid=5__cb=77d4645a81__oadest=https://wikimapia.org