On Sunday 17 November, 1912, demonstrations were held around Europe to protest at the escalating Balkans War. There were large demonstrations and mass meetings in London, Berlin, Paris, Amsterdam, Budapest, Madrid, Milan, Strasbourg and Christiania (Oslo) and smaller ones in many other cities.
The mass meetings and demonstrations were intended to build support for an extraordinary congress of the Second (Socialist) International, to be held in Basel (Switzerland) the following week.
The Times of London reported that the mass meeting in Paris had been advertised in "working-class quarters" by taxicabs displaying large placards.
The syndicalist Confédération Cénérale du Travail (CGT) didn't give its support to the mass meeting, owing to differences of approach between it and the parliamentary social democratic party, but many syndicates encouraged their members to attend.
According to the Times, police estimated the turnout to be 20-30,000. Socialist publications put the turnout at 100,000 . Speakers included Emile Vandervelde (Belgium), Engelbert Pernerstorferr (Austria), Ramsay MacDonald (UK), Philipp Scheidemann (Germany) and llya Rubanovich, representing the Russian Socialist Revolutionary Party. French socialist Jean Jaurès was in the meantime speaking at a demonstration in Berlin.
Jean Morin, councillor for Seine, told the huge crowd:
"The moment is serious: Europe is on the eve of a major war; you must overcome your cowardliness: Well! Rather than go to serve as cannon fodder for the sole benefit of capitalism, we have to respond to the government's call by complete silence, to refuse to obey any mobilisation order, and to go into the streets for the final insurrection."
It had apparently been agreed that there would not be a march following the mass meeting in Paris, but some people attempted to hold one anyway, and were dispersed by police.
In London, a meeting was held at Kingsway Opera House, chaired by Harry Quelch. Speakers included Ludwig Frank (Germany), Edward Anseele (Belgium), Jean Longuet (France) and Platon Drakoules (Greece).
Meanwhile, on the battlefields...
On the day of the Europe-wide demonstrations, Bulgarian forces began their attempt to break through the Ottoman defensive line at Çatalca, about 40 kilometres from Constantinople (Istanbul). The assault was called off the next day following heavy losses.
Russia had ambitions of its own over the Dardanelles and had already warned that it would attack its former protegé Bulgaria if Bulgarian forces captured Constantinople. If the Bulgarians had been successful and had marched on Constantinople, they might very well have triggered the start of World War 1.
At around the same time, Serbian forces reached the Adriatic at Alessio, which they were to capture on 19th November. Austria-Hungary was not willing to tolerate Serbian control of an Adriatic port, and was counting on German support if it went to war to reverse the Serbian gains. Serbia was counting on Russian support, and Russia hoped to have France on its side if it went to war with Germany. France in its turn expected British support.
Britain's Royal Navy had already raised the manning of its ships to wartime levels, a move that alarmed Germany though it was carried out under the cover of "exercises."
And in the chancelleries ...?
Later, in a rather optimistic article published in August 1914 (!)  George England wrote of the anti-war demonstrations that:
"The calming effect upon the various monarchs and chancelleries was astonishing and instantaneous."