The political unification of Italy enhanced Milan's economic dominance over northern Italy. A dense rail network, whose construction had started under Austrian patronage, was completed in a brief time, making Milan the rail hub of northern Italy and, with the opening of the Gotthard (1882) and Simplon (1906) railway tunnels, the major South European rail hub for goods and passenger transport. Indeed, Milan and Venice were among the main stops of the Orient Express that started operating from 1919. Abundant hydroelectric resources allowed the development of a strong steel and textile sector and, as Milanese banks dominated Italy's financial sphere, the city became the country's leading financial centre. Very rapid industrialization in the last two decades of the 1800s led to the birth of a massive worker class as well as bitter social conflicts. In May 1898 Milan was shaken by the Bava Beccaris massacre, a riot related to soaring cost of living.