This gigantic chalk figure carved into a hillside is Britain's oldest. Local historians fancy that it's linked with Alfred the Great, but it is now understood that it greatly predates that period. It was first mentioned in a 12th century manuscript as merely a landmark, mentioning a Manor House nearby. John Aubrey, the famous antiquarian (who is mostly famous now for just now wrong his assumptions here) guessed that it was carved by Hengist, because he rode a white horse and it was on his battle standard. A hundred years later Francis Wise claimed patriotically that Alfred the Great cut it to celebrate his defeat of the Danes at Ethandun in 878 ce, supposedly Ashdown in Berkshire. This notion of it being carved by the Anglo-Saxons remained unchallenged until 1931 when archaeologist Stuart Piggot, owing to the design of the horse itself, contested that it was of Celtic design and it must have been done around 100 bce. Over the intervening sixty years it went back and forth between the romantic notion of the Celts carving it and the Anglo-Saxons until the arrival of proper technology to discern dating evidence. With the advent of Optical Stimulated Luminescence, which can measure the time that has lapsed since the soil last saw sunlight, it was determined that the carving of the White Horse at Uffington had been carved far beyond anyone's wildest imagination. It was completed sometime in 1000bce. It remains the only hill figure dated by scientific evidence.
Speculations abound, some linking it with St. George and the Dragon - that the White Horse carved into the hillside is a monument to George's horse from the tale. Others claim it must be the Dragon.
Interestingly the legends and tales taper off and fall away as time goes by but one of the longest standing legends associated with it is that if you stand in the Horse's (Dragon's?) eye and make a wish, that it will most certainly come true.