ednesday night may have been London's quietest after a violent, days-long riot, but the city's residents and British Prime Minister David Cameron remain on edge. By Tuesday, 16,000 police converged on the city, enacting tougher measures to quell the violence, while copycat riots unfolded in other British cities. Londoners now face the wreckage — from chic Notting Hill in west London to gritty Hackney in the east — dealing with torched cars and taking inventory of what's left in looted stores. As authorities estimate the cost of the massive clean-up job in the tens of millions, the rioters' motives are still being debated, but police describe the uprising as one of the city's worst social upheavals in living memory. Here's a look back at some of London's other newsworthy clashes...