Qatar, Fuhairat, Ancient rock engravings of tribal sign.

Qatar, Fuhairat, Ancient rock engravings of animals.

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.

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.

England, Bristol, Detail of the engravings on the arch above the main door to Bristol Cathedral.

USA, Washington DC, National Mall, Lincoln Memorial, Martin Luther King march engraving in front of the peristyle commemorating his I have a dream speech during the March on Washington for Jobs and F...

Namibia, Twfelfontein bushmen carvings are one of the most important archeological sites in Southern Africa. The site has an extensive collection of pre-historic rock engravings, or pectoglifs, some d...