This year's Group of 20 summit, held in Germany, has featured awkward handshakes, colossal eye rolls and talk of a new trade war.

It has also played host to some massive protests. In Hamburg over the past few days, thousands of people have gathered to oppose — lots of things: globalization, free trade and President Trump. Activists staged sit-ins and threw bottles at police officers, who responded with water cannons and pepper spray. Some protesters shot firecrackers at a police helicopter. More than 100 police officers have been injured, and at least 45 protesters have been jailed.

Things got so bad that there were reports that first lady Melania Trump was unable to leave her hotel to attend an event.


Riot police chase protesters during clashes Friday in Hamburg. (Armando Babani/European Pressphoto Agency)

The pictures out of Hamburg are wild. But in truth, it's par for the course. The G-20 has always attracted a rowdy crowd. As Julia Kulik, a researcher with the University of Toronto's Munk School of Global Affairs explained, the event draws a crowd of people opposed to “corporate greed.”

“The G-20 was founded to make globalization for the benefit of all,” Kulik told Global News. But activists — many with an “anti-capitalist” bent — suggest that the summit isn't really “for the people.”

They point to the 2008 U.S. bank bailouts, the fact that most of the summit meetings are private and the lack of focus on the poor. “Seeing 20 to 21 people making decisions that affect the entire world is not appealing to a lot of people,” Kulik said.


Police forces use a water cannon to disperse protesters during the G-20 summit Friday in Hamburg. (Ronald Wittek/European Pressphoto Agency)

G-20 protesters march Friday in Hamburg. (Alexander Koerner/Getty Images)

In London in 2009, about 4,000 people gathered in the city's financial district before the meeting began. Relations between the activists and the police were tense throughout the conference — at one point, police charged a sit-in in the city center. There were at least 145 allegations of police brutality (one person collapsed and died after being knocked down; others said police hit them with batons), and several officers were reprimanded.


Police charge into a crowd of demonstrators in London ahead of the G-20 summit in 2009. (Matt Cardy/Getty Images)

A climate-change protester wearing a horse mask reads a fake copy of the Financial Times during a G-20 demonstration in London in 2009. (Adrian Dennis/Getty Images)

Bloodied protesters shout at police as anti-capitalist and climate-change activists demonstrate in London in 2009. (Oli Scarff/Getty Images)

A similar scene met world leaders in Toronto in 2010. During that G-20 summit, there were protests throughout the city, leading to the largest mass arrest in Canadian history. At least 1,000 people were sent to detention centers, and a report later found widespread violation of protesters' civil rights.

Of course, not every G-20 meeting results in a major showdown. The 2014 Brisbane summit was relatively quiet, probably because it's harder for international activists to get to Australia. And in China last year, where protest is tightly controlled, there were few demonstrations, and some journalists were arrested.