The city of Rio had a busy Sunday: 3,000 heavily armed police and military troops swarmed one of the city's largest favelas as part of a massive effort to secure the city in anticipation of the 2014 World Cup and 2016 Summer Olympics. Explore operation "Shock of Peace" in this slideshow.

The raid, dubbed a "pacification" effort, began at dawn, with military helicopters and armored vehicles descending on the narrow streets of Rocinha. As they patrolled the alleys, snipers peered through gun sights from atop neighboring buildings. The effort was met with little resistance, as you'll see in these images, leading some to say it was wild overkill. In the end, not a single shot was fired. [NYT, Photo Credit: AP]

A police helicopter circles over Rocinha. [Photo Credit: AP]

Police officers aim their guns at nothing in particular. [Photo Credit: AP]

Earlier in the week, Antonio Bonfim Lopes, aka "Nem," was escorted handcuffed by police at the federal police headquarters. He is considered the most wanted drug kingpin in Rio. [Photo Credit: AP]

Brazilian navy tanks move into the Rocinha slum. [Photo Credit: AP]

A bored woman observes the raid from her windowsill. [Photo Credit: AP]