Austria, Salzburg, General view of the city and river Salzach from the Festung Hohensalzburg Fortress above the city with hills in the background.

USA, Massachusetts, Boston, Pierce Hichborn House, North Square, North End.

USA, Massachusetts, Boston, Sign outside Pierce Hichborn House, North Square, North End.

USA, Massachusetts, Boston, Sign outside Paul Revere House, 19 North Square, North End.

USA, Massachusetts, Boston, Paul Revere House, 19 North Square, North End.

USA, Massachusetts, Boston, Custom House, McKinley Square.

Iceland, Reykjavik, Parliament Building, Althingishusid, Austurvollur Square.

USA, New York City, Manhattan, New York Fire Department Memorial Wall, Engine 10, Ladder 10, World Trade Center.

USA, New York City, Manhattan, One of the two waterfalls at National September 11 Memorial, World Trade Center.

USA, New York City, Manhattan, One of the two waterfalls at National September 11 Memorial, World Trade Center.

USA, New York City, Manhattan, Four World Trade Center also known as Tower 4 and 150 Greenwich Street.

USA, New York City, Manhattan, One of the two waterfalls at National September 11 Memorial, World Trade Center.