H ow do you measure how much drugs a city’s residents are using? One way is to check the sewers. According to new research from the E.U., London residents flush away the most cocaine of any major European city.
The study, which looked at 50 cities around Europe, found that 737 mg of cocaine was flushed per 1,000 people each day last year, according to the BBC. Amsterdam came in second place with 716 mg, and Antwerp in third with 632 mg.
Peak days for cocaine-flushing in London are Fridays and Saturdays, with Sundays and Mondays showing a significant drop-off.
[BBC ]
What America's War on Drugs Looked Like in 1969 A U.S. Customs agent points his gun at a car suspected of transporting marijuana, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agents tailing a suspected drug smuggler, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Drug bust outside of San Antonio, Texas, part of U.S. Customs' "Operation Intercept," 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images The U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images The U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene from U.S. Customs' anti-drug smuggling effort, "Operation Intercept," along the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images The U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene at the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Suspected drug smugglers searched at the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Scene at the U.S.-Mexico border, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Customs agents, Texas, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Customs agents, Texas, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Customs agents, Texas, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Customs agents with suspected drug smugglers, Falcon Lake, Texas, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Caption from LIFE. At sunset, Customs agents, armed with shotguns, scour the darkening waters of Falcon Lake, Texas -- a favorite border-crossing point for smugglers.Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agents in a car filled with seized marijuana. Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agent, 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agents unload seized marijuana. Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agents in a car filled with seized marijuana. Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agent in a room filled with seized marijuana. Co Rentmeester—The LIFE Picture Collection/Getty Images Caption from LIFE. A 500-pound cache of confiscated marijuana is removed from warehouse-like storage vault in San Diego, then burned in raging furnace, one brick at a time." (See last image in gallery.)Co Rentmeester—The LIFE Picture Collection/Getty Images U.S. Customs agents with seized marijuana. Co Rentmeester—The LIFE Picture Collection/Getty Images Room filled with seized marijuana, San Diego, Calif., 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images Seized marijuana burns in a furnace, San Diego, Calif., 1969. Co Rentmeester—The LIFE Picture Collection/Getty Images More Must-Reads from TIME