Short answers, pulled from the story.
Regensburg sits in eastern Bavaria at the point where the Danube reaches its northernmost bend and meets the rivers Naab and Regen. It is the capital of the Upper Palatinate subregion and the fourth-largest city in Bavaria, with more than 150,000 inhabitants.
Regensburg's medieval centre was added to the UNESCO World Heritage list in July 2006. UNESCO cited it as the largest well-preserved medieval city site north of the Alps and noted its historical role hosting assemblies of the Holy Roman Empire.
In 1519, following the death of Emperor Maximilian I, Regensburg's city council and guilds expelled the city's medieval Jewish community. About 500 Jews were forced out, their property was confiscated, and the synagogue and much of the Jewish quarter were demolished.
Regensburg was bombed by the Allies on the 17th of August 1943 and again on the 5th of February 1945, targeting a Messerschmitt Bf 109 factory and an oil refinery. Both facilities were severely damaged, but the wider city and its medieval centre suffered only minor harm.
The Perpetual Diet of Regensburg was the permanent seat of the Holy Roman Empire's Imperial Diet, held in the city from 1663 to 1806. It made Regensburg a functional co-capital of the Empire, second only to the Emperor's court in Vienna.
Notable figures connected to Regensburg include the astronomer Johannes Kepler, Pope Benedict XVI, who taught theology at the University of Regensburg from 1969 to 1977, and footballer Kenan Yıldız, born in the city in 2005.