
In the southern part of Britain, just a little bit north of Stonehenge and northeast of the massive Avebury stone circles just off Dragon Hill Road on White Horse Hill there is a famous relic from the bronze age, about 1,000 B.C. In Google Earth look at 51.578920,-1.568262
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For some reason the Celts dug away the top soil (thus exposing the chalk underlaying it) and made a beautiful abstract modern-art image of a horse. The horse is really big, measuring in at 110 meters long (374 feet).
In fact there are many other white horses both in Wiltshire, UK and even a few abroad.
Link: http://wiltshirewhitehorses.org.uk/foreign.html
Without any doubt the most famous white horse is this one at Uffington.

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The local architect Hector Garcia Acosta has made a copy of the reverse image of this famous Uffington horse using whitewash. This one in Mexico is 960 meters long, or more than a half-m

In Google Earth look at 31.662032,-106.588063
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