11. Want to stabilize your beam bridge? Try adding trusses. The triangular supports, a common feature of shorter-span railway bridges, give the deck greater rigidity, which dissipates, or distributes, both compression and tension forces.
12. For longer spans, engineers may turn to suspension bridges. The deck is suspended by cables (stretched with tension), which hang from towers (compressed into the ground).
13. Arch bridges, popular since antiquity, are more stable than the beam variety. The entire bridge is under compression, which is dissipated out and down from the center — right into the supports.
14. Bridges need to be stable, but bridges themselves can also provide stability. Disulfide bridges, for example, hold together the different protein chains that make up an antibody. You can think of them as the glue in immunoglobulin molecules, the warriors of the immune system.
15. A different bridge keeps people glued to their seats: the card game. Today’s Bridge evolved from earlier games such as Whist. Some of its predecessors date to the 16th century.
16. The game’s name is an Anglicization of the word biritch, which some historians believe has Russian origins. Its roots may be in Turkey, however, where it was a popular diversion among expats, including Russians, nearly two centuries ago.
17. Some bridges still in use today have even older roots. The sturdily built Pons Fabricius arch bridge has connected Tiber Island to the heart of Rome since 62 B.C.
18. You can thank those industrious Romans for building the world’s oldest reliably dated bridge, too: They erected a stone arch span over the Meles River in Izmir, Turkey, in the ninth century B.C.
19. The Meles bridge is used even now, as is the Kazarma, or Arkadiko, bridge in southern Greece. Built from unworked limestone boulders and rocks, the basic arch, though never conclusively dated, may be from the 14th century B.C.
20. Can’t credit the Romans with this one, though. The 22-meter-long Kazarma is an example of Mycenaean Bronze Age masonry. In your face, Romans!