Protests around the world on Saturday called for an end to the US-led occupation of Iraq and Israel's claims on Palestinian territories.
Spanish demonstrators' said: 'No Occupation in Iraq and Palestine'
In London, about 20,000 people were estimated by police to have demonstrated against continuing military involvement in Iraq.
But numbers were well down on the huge demonstrations seen before the war, in February.
Marches also took place in other European countries and in South Korea with protests planned in the US later on Saturday.
Many demonstrators were angry with the coalition's failure to unearth any weapons of mass destruction in Iraq.
"It was all lies," said British protester Peter Mason, 45. "The millions who demonstrated before the war were right."
About 3,000 demonstrators marched through Paris, rallying against US President George W Bush and Israeli Prime Minister Ariel Sharon.
They shouted "Bush, Sharon - Assassins" and accused the leaders of not doing enough to foster peace in the Middle East.
Other demonstrators were angry about the situation in Iraq following the US-led military campaign.
Protestors in Lebanon shouted pro-Saddam Hussein slogans
"There is a lot to be done, the whole country needs to be re-built," said Venetia Valin, 52.
"There is no electricity, there is no sanitary system anymore. It's a huge job and it's too expensive for the United
About 400 people demonstrated outside the Reichstag parliament building in Berlin, Germany.
"Iraq and Afghanistan are all part of a big game. It is all about oil," said Emanuel Bertelsmann, 24, waving an Iraqi flag.
In the Greek capital, Athens, about 3,000 demonstrators confronted riot police outside the American embassy, chanting: "Occupiers out" and "Freedom for Palestine".
The Austrian capital saw about 200 protesters gather in a central square.
And in the South Korean capital, Seoul, more than 2,000 people marched on the city centre to oppose the sending of South Korean troops to Iraq.