Massive protests are taking place in Hamburg, Germany as the G20 summit of some of the world's leading economies gets underway.

Specifically, the anti-capitalist protesters, thousands of them, are demonstrating against free trade deals, which they say hurt middle class workers. Others are protesting the G20 members' environmental impact. They have dubbed their protest "Welcome to Hell."

It has gotten so dangerous that SWAT teams have assembled on the streets and police have even employed water cannons and tear gas to try and control the crowds.

Police move in water cannons at G20 for crowd control. pic.twitter.com/CYve5EpRsD — Fox News (@FoxNews) July 6, 2017

As you can see, the protests have become violent.

BREAKING NEWS: Anti-Globalization protesters at G20 summit. pic.twitter.com/M9hDMeJMo4 — Fox News (@FoxNews) July 6, 2017

Some activists are even throwing glass, stones, and iron bars at police, according to Sky News. Many protesters are in disguise.

7.11pm: The Sky News crew was forced to run for cover to avoid an incoming rain of glass bottles. 7.06pm: According to a Sky News reporter on the scene of the protests, the angry protesters clad in black were tossing objects back at the police. The video crew at the frontline of the protests caught several glass projectiles crashing around it.

Several businesses have closed up shop in fear of potential damage. Yet, some storefronts have already been set on fire.

President Trump arrived in Germany Thursday, where he met German Chancellor Angela Merkel. In addition to trade, the leaders are expected to discuss climate change, migration, and terrorism.