Wrocław (German: Breslau), situated on the Oder river, is the largest city in western Poland (630,000 inhabitants in 2010). It started as a Bohemian town and was later incorporated in the Austrian Empire. Prussia conquered the city during the word wide War of the Austrian Succession (in the US better known as King George's War) in the 1740s. The city became the capital of the province of Silesia.
In 1806-1807 the city was temporarily occupied by the French troops of Napoleon's youngest brother Jerome. He decided to level the city walls. By the end of the 19th century it was the third largest German city (behind Berlin and Hamburg).
Breslau didn't suffer much until the end of WWII. Hitler declared the city a fortress to be held at all costs. The population was forced to evacuate, and a large area of the city center was demolished and turned into an airfield. After a siege of nearly three months Breslau was the last major German city to surrender, one day before the end of the war in Europe.
During the Potsdam Conference the Western Allies proposed to grant Germany half Silesia, Breslau included, but the Soviets insisted the border to be drawn farther west.
Nearly all Germans were expelled from the city and replaced by Poles who for a large part were forcefully deported from Polish lands annexed by the Soviets in the east, many of whom came from Lviv.
After the war the city's historical monuments have been carefully rebuilt.
Ostrów Tumski (Cathedral Island) is the oldest part of the city. It is located between branches of the Oder River (source+more pics: Grzybson88)