Protesters clash with riot police during a demonstration against President Barack Obama's visit to Athens on Nov. 15, 2016.
Greek police say about 3,000 anarchists, left-wing activists and students marched through central Athens.
There's a strong anti-American tradition among Greek left-wingers, who still resent U.S. support for Greece's 1967-74 military dictatorship.
Protesters clash with the police.
Protesters hold a banner that reads "Not welcome - against Obama's visit."
Protesters run from teargas.
Protesters burn a U.S. flag.
A man tries to extinguish a garbage bin set on fire by protesters.
Protesters stand in front of graffiti that reads 'No Hope.'
Fire from a molotov cocktail rises near Greek riot police.
Protesters prepare to throw molotov cocktails during clashes.
Demonstrators hold a placard reading 'Trump - build a wall around your face.'
A protester jumps to avoid tear gas as another prepares to throw a firebomb.
Demonstrators cover their faces and disperse as tear gas is fired during clashes.
Riot police stand on a street amid tear gas.
PHOTOS: Obama Tours Acropolis in Athens