In 1795, Lithuania became part of the Russian Empire. Poles and Lithuanians unsuccessfully rebelled against Russian authorities. These uprisings are connected with the beginnings of the hill: as families could not locate bodies of perished rebels, they started putting up symbolic crosses in place of a former hill fort.
When the old political structure of Eastern Europe fell apart in 1918, Lithuania once again declared its independence. Throughout this time, the Hill of Crosses was used as a place for Lithuanians to pray for peace, for their country, and for the loved ones they had lost during the Wars of Independence.
Most recently, the site took on a special significance during the years 1944–1990, when Lithuania was occupied by the Soviet Union. Continuing to travel to the Hill and leave their tributes, Lithuanians used it to demonstrate their allegiance to their original identity, religion and heritage. It was a venue of peaceful resistance, although the Soviets worked hard to remove new crosses, and bulldozed the site at least three times (including attempts in 1963 and 1973).
Today the hill remains under nobody's jurisdiction; therefore people are free to build crosses as they see fit.
From: http://en.wikipedia.org/wiki/Hill_of_Crosses
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