A significant police operation is underway in Cologne, Germany, following an explosion in the city center on Monday. The blast occurred at around 6 a.m. near the Vanity nightclub in the Hohenzollernring area, a central entertainment district, injuring at least one person. Authorities have sealed off the area and advised residents to avoid it. This incident follows another explosion just two days prior, only 100 meters away. The cause of the explosion remains unclear, and police are analyzing CCTV footage as part of their ongoing investigation. The explosion reportedly caused a fire, which has since been extinguished.