Press down on the center of the bridge. What happens to the top and bottom notches? Notice how the top notch squeezes together in compression, while the bottom notch spreads apart under tension.

Built before the birth of Christ, the bridge is held together by mortar only in its top tier; the stones in the rest of the structure stay together by the sheer force of their own weight.

Icons of the 1970s international folk scene, Alan Allen and Duncan Bridge were suddenly forced into ‘retirement’ in 1978 while at the height of their fame. An inspiration for a generation of ...