Geograph Britain and Ireland is a web-based project, initiated in March 2005, to create a freely accessible archive of geographically located photographs of Great Britain and Ireland. Photographs in the Geograph collection are chosen to illustrate significant or typical features of each 1 km × 1 km (100 ha) grid square in the Ordnance Survey National Grid and the Irish national grid reference system. There are 331,957 such grid squares containing at least some land (at low tide). Each page uses a Geo microformat.