Booming firecrackers, acrid smoke from burning bales of hay, and tractors blocked the roads outside the European Commission in Brussels, where more than 1,000 demonstrators vented their anger at the EU for pursuing free trade policies.
Singing and holding flags and banners aloft they filled the street in the driving rain.
But there was a strong smell of desperation too, as the marchers realised that EU leaders had ended their summit and gone home a day early.
There is mounting concern among Belgian farmers and small-scale entrepreneurs that the big multinationals will hijack key trade negotiations between the EU and US.
Those negotiations - called TTIP - were on the summit agenda.
European Commission President Jean-Claude Juncker said the aim was to wrap up the talks by the end of next year.
Most observers say that is a very ambitious schedule. So far progress has been slow, as there are fundamental differences between the EU and US economies.
There are also arguments over the big state subsidies that farmers get on both sides of the Atlantic.
UK Prime Minister David Cameron is among the enthusiastic backers of TTIP in Europe.
Business federations, including Britain's CBI, say thousands of jobs could be created but unions argue that health services would end up being privatised.
What is TTIP?
The Transatlantic Trade and Investment Partnership, now generally known as TTIP, is primarily a deal to cut tariffs and regulatory barriers to trade between the US and EU countries, making it easier for companies on both sides of the Atlantic to access each other's markets.
Industries it would affect include pharmaceuticals, cars, energy, finance, chemicals, clothing and food and drink.
The European Commission says that, according to independent research, a free trade deal with the US could generate an extra €120bn (£94bn; $147bn) for the European economy and €90bn for the US, as well as many new jobs.
Anti-TTIP activists warn of a "race to the bottom", with an erosion of living standards. They say the welfare gains of European workers since World War Two must be defended and point to the inequalities that plague US society.
At EU institutions "there are too many lobbyists for big business - it's not fair", said Tijs Boelens, a Belgian vegetable grower.
He said dairy farmers were especially angry about low milk prices and their struggle to make a profit.
"We want food sovereignty - without that there is no future for us farmers."
Paul Rixen was representing a Belgian welfare solidarity group linked to the Catholic relief agency Cafod.
For him, TTIP "means competition in health, the environment, the lowest common denominator," he told the BBC.