View of Tower Bridge and the Tower of London, UNESCO World Heritage Site, from Cheval Three Quays at dusk, London, England, United Kingdom, Europe

View of the Tower of London, UNESCO World Heritage Site, and Tower Bridge from Cheval Three Quays at sunset, London, England, United Kingdom, Europe

View of the Tower of London, UNESCO World Heritage Site, and Tower Bridge from Cheval Three Quays at dusk, London, England, United Kingdom, Europe

View of the Tower of London, UNESCO World Heritage Site, from Cheval Three Quays at sunset, London, England, United Kingdom, Europe

View of the Tower of London, UNESCO World Heritage Site, from Cheval Three Quays at dusk, London, England, United Kingdom, Europe

Castle of the Three Kings of Morro, UNESCO, Havana, Cuba

Castle of the Three Kings of Morro, UNESCO, Havana, Cuba

Castle of the Three Kings of Morro in foreground, UNESCO, Havana Skyline in the background, Havana, Cuba

Castle of the Three Kings of Morro, UNESCO, Havana, Cuba

Fortress of the Three Cities (Cospicua, Senglea and Vitoriosa), Malta, Mediterranean, Europe

View from Valletta to the Three Cities under blue sky, Malta, Europe

Three Cities (Cospicua, Senglea and Vitoriosa), Malta, Mediterranean, Europe

Three Cities (Cospicua, Senglea and Vitoriosa), Malta, Mediterranean, Europe