With the end of the 19th century the area was subsumed into the surrounding Polish Downtown and the area adjacent to the park which gave the neighborhood its name became known as "the Polish Gold Coast". In the 1890s and 1900s, immigration from Poland and the completion of the Metropolitan West Side Elevated Lines greatly boosted the population density of West Town, especially in areas east of Wicker Park. The area around Division, Milwaukee, and Ashland was once known as 'Kostkaville', and the intersection retains the moniker "Polish Triangle" to this day. The provisional government of Poland met in Wicker Park during World War I. The near Northwest Side is home to many of the most opulent churches in the Archdiocese of Chicago, built in the so-called 'Polish Cathedral style'.