Prague cityscape looking down the Vltava River at its bridges connecting the Old Town to Mala Strana, Prague Castle and Hradcany, Prague, Czech Republic, Europe

City of London skyscrapers viewed across the River Thames, London, England, United Kingdom, Europe

Belvedere Castle and Turtle Pond, Central Park, Manhattan, New York City, New York, United States of America, North America

Belvedere Castle and Turtle Pond, Central Park, Manhattan, New York City, New York, United States of America, North America

Belvedere Castle and Turtle Pond, Central Park, Manhattan, New York City, New York, United States of America, North America

High angle view of Charles Bridge looking towards the Castle District, Royal Palance and St. Vitus's Cathedral, UNESCO World Heritage Site, Prague, Czech Republic, Europe

High angle view of Charles Bridge looking towards the Castle District, Royal Palace and St. Vitus's Cathedral, UNESCO World Heritage Site, Prague, Czech Republic, Europe

High angle view of Charles Bridge looking towards the Castle District, Royal Palace and St. Vitus's Cathedral, UNESCO World Heritage Site, Prague, Czech Republic, Europe

Looking down the Vltava River to Manesuv, Charles and Legii bridges connecting the Old Town to Mala Strana, Prague Castle and Hradcany, Prague, Czech Republic, Europe

High angle view of Charles Bridge looking towards the Castle District, Royal Palace and St. Vitus's Cathedral, UNESCO World Heritage Site, Prague, Czech Republic, Europe

Prague cityscape looking down the Vltava River at its bridges connecting the Old Town to Mala Strana, Prague Castle and Hradcany, Prague, Czech Republic, Europe

St. Vitus's Cathedral and Prague Castle illuminated at dusk, UNESCO World Heritage Site, Prague, Czech Republic, Europe

Cityscape looking down the Vltava River at the bridges connecting the Old Town to Mala Strana, Prague Castle and Hradcany, Prague, Czech Republic, Europe

View of Charles Bridge, the Castle District and St. Vitus's Cathedral across the Vltava River at sunset, Prague, Czech Republic, Europe

Clifford's Tower, York Castle, York, North Yorkshire, England, United Kingdom, Europe

Clifford's Tower, York Castle, York, North Yorkshire, England, United Kingdom, Europe

Riga Castle, Riga, Latvia, Europe

City of London skyscrapers and the Tower of London viewed across the River Thames, London, England, United Kingdom, Europe

Riga Castle, Riga, Latvia, Europe

Castle Fraser, a 16th century castle, the grandest of the castles of Mar, near Inverurie, Aberdeenshire, Scotland, United Kingdom, Europe

PORTUGAL, ALGARVE, SILVES, VIEW OF TOWN AND CASTLE

PORTUGAL, ALGARVE, SILVES, SILVES CASTLE

PORTUGAL, ALGARVE, SILVES, SILVES CASTLE