inches on all of the stones in 2 years and 9 months Persistence and determination! How were they put in place? A simplistic view Stones were sunk 3 to 5 feet into the ground. One side of the hole was a wooden ramp. Wooden stakes were used to reinforce the other sides of the hole. 140 200 workers would pull the stone upright perhaps using a pulley. The hole was filled with rocks and boulders packed tightly together. Mortise, tenons, and toggle joints were used to hold the lintels and sarsens together. Why?? Theories-why was it built? Predict astronomical events. 30 sarsens in the circle could symbolize the days of the month 19 bluestones in the horseshoe could be the 19 year cycle of the moon Aligned with the midsummer sunrise and midwinter sunset Sacred site Who built it?? Merlin, the magician in King Arthur's time moved the stones to honor soldiers Built by Roman invaders
bridge has been discovered in South Wales (UK) at Merthyr Tydfil, a major early 19th century iron- producing centre. Pont-y-Cafnau (Bridge of Troughs) is a unique cast-iron combined aqueduct tramroad bridge below the confluence of the Taff and Taff Fechan, built in January-June 1793 by Watkin George, Chief Engineer of the Cyfarthfa Ironworks, to carry an edge railway and water channel. An iron trough-like girder is carried in an A-frame truss of cast iron spanning 47ft (14.2m), held together by mortise-and-tenon and dovetail joints. The next extant iron railway bridge seems to be another recently discovered at Aberdare (1811), followed by Gaunless. The oldest still in service is Hall's Station Bridge, a Howe truss designed in 1846 by Richard Osborne, a London-born Irishman who worked as engineer for the Philadelphia & Reading Railroad, although its current use is vehicular and not rail. The first major iron truss with pin connections was built in the USA in
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