When Jan van Valckenborgh introduced a second layer to the fortifications to protect against the Thirty Years War in the seventeenth century, he extended Hamburg and created a “New Town” (Neustadt) whose street names still date from the grid system of roads he introduced.
In 1842, about a quarter of the inner city was destroyed in the “Great Fire”. The fire started on the night of 4 May and was not extinguished until 8 May. It destroyed three churches, the town hall, and many other buildings, killing 51 people and leaving an estimated 20,000 homeless. Reconstruction took more than 40 years.