id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
en-wikipedia-org-4931		Xerxes' Pontoon Bridges - Wikipedia			.html	text/html	5317	352	79	Xerxes' Pontoon Bridges were constructed in 480 BC during the second Persian invasion of Greece upon the order of Xerxes I of Persia for the purpose of Xerxes' army to traverse the Hellespont (the present day Dardanelles) from Asia into Thrace, then also controlled by Persia (in the European part of modern Turkey).[1] After Herodotus hardly indicated the location of the pontoon bridge across the Bosphorus built some 30 years earlier by Xerxes' father Darius I, but did not provide any specific information about that bridge, the wealth of details given for the bridges across the Hellespont is astonishing and, upon cursory reading, seems to provide a clear picture. Because of the current and the lateral wind forces, they would have described a large curve allowing for a sort of horizontal sag of the cables in order to prevent the tension to increase indefinitely.[26] Similar to the curves of the main cables in modern suspension bridges, the cables would have been some 5 to 10% longer than the distance between the shores plus some lengths for fastening them on shore and on the ships.	./cache/en-wikipedia-org-4931.html	./txt/en-wikipedia-org-4931.txt