Odrzykoń

Poland

Odvoș

Romania

Odzaberd

Armenia

Ogra

Romania

Ogrodzieniec Castle

Poland

Oheka Castle

the United States

Oituz

Romania

Ojców Castle

Poland

Oka Castle

Japan

Okartowo

Poland

Okayama Castle

Japan

Okazaki Castle

Japan

Okić Castle

Croatia

Okopy Castle

Ukraine

Olana

the United States

Oland House

Canada

Old Castle

Hungary

Old Castle in Płoty

Poland

Old Chortkiv Castle

Ukraine

Old Crom Castle

Ireland

Old Fortress, Corfu

Greece

Venetian period

Old Fortress, Livorno

Italy

Old Ganja Castle

Azerbaijan

Old Georgia State Capitol

the United States

Old Litava Castle

Slovakia

Old Louisiana State Capitol

the United States

Old Main

the United States

Old Navarino castle

Greece

Frankish period

Old castle of de Hollogne-sur-Geer

Belgium

Old town of Visoki

Bosnia and Herzegovina

Olderfleet Castle

Ireland

Olesko Castle

Ukraine

Oleszyce

Poland

Oleśnica Castle

Poland

Olimje Castle

Slovenia

Olsborg

Norway

Ruin