1888 and 1889. In 1889 Emperor Wilhelm II visited the city to inspect the flood damage, and appointed a committee to take steps to prevent further such disasters. The small river branch called the Zgniła Warta ("rotten Warta") flowing west of Grobla (on the line of today's ul. Mostowa) was filled in, as was a stream following into it (today's ul. Łąkowa). It was also planned to divert the main stream of the Warta to flow east of Chwaliszewo (in what was then a flood relief channel), but this plan would not be realized until 1968 (further major floods would occur in 1924 and 1940). Poznań gained its first electric trams in 1898 (horse-drawn trams had operated since 1880, running from the new rail station to the Old Market Square, and later to the cathedral; see Tramways in Poznań). The first motor cars were seen on the city's streets in 1901, and the first taxis in 1905. In 1896 the right-bank suburbs of Piotrowo and Berdychowo became part of the city. The city borders were then expanded significantly westwards in 1900, to include the former villages of Łazarz, Górczyn, Jeżyce and Wilda. Sołacz was added in 1907. Poznań now covered an area of . In 1911–1913 the St. Roch road bridge was built across the Warta close to Berdychowo (a bridge had previously stood there until 1771). Interwar period Following Germany's defeat in World War I Polish independence seemed assured, but it was not clear whether Greater Poland would become part of the new state of Poland. A speech given in Poznań by Ignacy Paderewski on December 27, 1918 ignited the Greater Poland Uprising of 1918–1919, in which Polish troops attempted to take control of the region from Germany. The uprising was largely successful, and in the Versailles peace treaty (signed June 28, 1919) most of the region was granted to Poland, with Poznań as the capital of the newly formed Poznań Voivodeship within the Second Polish Republic. Many German inhabitants left to live within the new German borders, partly because of discrimination. Germans made up 5.5% of the city's population in 1921, and 2.6% in 1931 (after the expansion of the city's boundaries). In 1919 Poznań University was opened, taking over the buildings of the Prussian Settlement Commission and Royal Academy. In 1921 Poznań first hosted trade fairs, which from 1925 became the Poznań International Fairs. From 16 May