Częstochowa entered the 20th century as one of the leading industrial centres of Russian Poland (together with Warsaw, Łódź, and Zagłębie Dąbrowskie). The city was conveniently located on the Warta and other smaller rivers ("Kucelinka, Stradomka, Konopka"). Real estate and land prices were low, compared to Łódź. The monastery attracted numerous pilgrims, who also were customers of local businesses. In 1904, Częstochowa had 678 smaller workshops, which employed 2,000 workers. In 1902, rail connection to the Prussian border crossing at Herby Stare was opened, and in 1911, the line to Kielce was completed. The Revolution in the Kingdom of Poland (1905–1907) began in Częstochowa as early as May 1904, when first patriotic rallies took place. On December 25, 1904, a man named Wincenty Makowski tried to blow up a monument of Tsar Alexander II, which stood in front of the monastery. In February 1905, a general strike action was declared in the city, with workers demanding pay rises. In June 1905 street clashes took place in Częstochowa, in which 20 people were killed by Russian forces. Further protests took place in 1909 and 1912.