Collodion print from a negative taken by Francis Frith. The Great Wall of China is one of the seven wonders of the modern world, and stretches for 4,500 miles. Built under the rule of three dynasties, it is over 2000 years old, and although much of it has deteriorated, it is still one of the most remarkable structures on the earth, visible from space. Francis Frith (1822-1898) was a travel photographer, who travelled to the Middle East three times between 1856 and 1860. He went on to set up a postcard busines, taking photographs of towns and villages all over Britain, for which he is now famous.
© National Museum of Science & Media / Science & Society Picture Library