The Samrat Yantra in Jaipur, India is the largest sundial ever built. Its gnomon is 73 ft. The sundial is part of the Jantar Mantar complex in Jaipur, India, one of five large astronomical observatories constructed out of stone by Jai Sing II between 1727 and 1734.

A French artist/scientist named Laurent Maget has done one better, by using the 150 ft. spire of the Mont Saint-Michel abbey as the gnomon of a giant sundial.
Mont Saint-Michel is a small rocky tidal island in Normandy, roughly one kilometre from the north coast of France. Rising from a hazy expanse of sand and waves, Mont Saint Michel appears like Man’s defiance of the elements and of time. Suspended high on the rock, the abbey calls you to discover the wild ambition of its builders and of those who, since 708, had wanted to make this isolated spot a meeting place for all people.

Manet used 600 one-meter reflective plates to create huge Roman numerals, placed in the surrounding tidal flats by the French army. The spire cast a shadow as long as three-quarters of a mile. At that size you can actually see the sun’s shadow moving as the minutes tick by. The panels stayed up for several weeks and then were then removed, but you can see a video of the incredible sundial in action.

For more sundial fun, check out the North American Sundial Society website- it’s full of cool info!

Thanks to the always-fascinating Spurgeonblog and Moonriver!