Hand-coloured photoscopic view of the interior of St Peter's Basilica, Vatican City, Rome, published by Frith and Co in about 1870. Built on the site of a Roman circus, the altar in the basilica marks the traditional spot of the martyrdom of St Peter. Although there has been a church on this spot since the fourth century, the current church was largely rebuilt in the sixteenth century. Photoscopic views were large format photographs on transparent paper designed to be looked at using a special viewer, similar to Carlo Ponti's Megalethoscope. Francis Frith (1822-1898) was a pioneer of travel photography. He was also one of photography's greatest entrepreneurs, founding a company that was to become the largest publisher of photographs in the world.
© Kodak Collection / National Science & Media Museum / Science & Society Picture Library