Leah Mills/Reuters Massive throngs of people hit the streets on Saturday in cities across the United States for the March for Our Lives protests against gun violence in the wake of last month's high-school shooting in Florida. The main event kicked off in Washington, DC, but cities like New York City, Los Angeles, Chicago, and many others held solidarity rallies that collectively drew out hundreds of thousands of protesters. Here's what the scenes looked like from above:Protesters packed Pennsylvania Avenue in Washington, DC. Associated Press/Alex Brandon The aerial photos are incredible. Reuters/Eric Thayer Organizers estimated that roughly 800,000 people turned up to the main event in DC. Associated Press/Alex Brandon Source: NBC News See the rest of the story at Business InsiderSee Also:'You can't fix stupid but you can vote it out': Here are some of the best signs from the March for Our Lives protests'Fight for your lives before it's someone else's job': Parkland student Emma Gonzalez sends a powerful message at the 'March for Our Lives' rallyTens of thousands of protestors in Washington take aim at politicians and the NRA to end gun violenceSEE ALSO: 'You can't fix stupid but you can vote it out': Here are some of the best signs from the March for Our Lives protests DON'T MISS: 'NRA sashay away': 175,000 people took to the streets for New York City's 'March for Our Lives' rally