Amsterdam-Zuid (; Amsterdam South) is a borough (stadsdeel) of Amsterdam, Netherlands. The borough was formed in 2010 as a merger of the former boroughs Oud-Zuid and Zuideramstel. The borough has almost 138,000 inhabitants (2013). With 8,500 homes per square kilometer, it is one of the most densely populated boroughs of Amsterdam. It has the highest income per household of all boroughs in Amsterdam. History Amsterdam-Zuid is the borough of Amsterdam situated to the south and southwest of the Singelgracht canal, along the Stadhouderskade city ring road. It is bordered by the Vondelpark in the northwest, the Westlandgracht canal in the west, the Amstel river in the east and the Kalfjeslaan in the south, which also forms the border with the municipality of Amstelveen. The Singelgracht canal had been Amsterdam's city border since the 17th century, when the Amsterdam canal belt was constructed. The taking down of the wall surrounding the Singelgracht, the outer canal, in the second half of the 19th century allowed for the development of new residential areas. South of the former wall, the first neighborhoods to develop were the Oude Pijp neighborhood, the neighborhood surrounding the Rijksmuseum, and the Willemspark neighborhood. This area is now also known as Oud Zuid ('Old South'). In 1917, the area was further developed southwards on the basis of Plan Zuid, the ambitious urban expansion plan designed by Dutch architect and city planner Hendrik Petrus Berlage. Berlage's plan included wide streets lined with four-story apartment blocks for the middle class. The plan also included public art to be installed in the new residential areas. Between 1920 and 1940, the Plan Zuid neighborhoods of Nieuwe Pijp, Diamantbuurt, Rivierenbuurt, Stadionbuurt and Apollobuurt were constructed, with many buildings designed in Amsterdam School style. This area is also known as Nieuw Zuid ('New South'). Another neighborhood built in the 1920s is the Hoofddorppleinbuurt, west of the Schinkel river. This neighborhood is part of Plan West, another urban expansion plan by Berlage which was designed for the western area of the city on the territory of the former municipality of Sloten. In the 1950s and 1960s, the Buitenveldert neighborhood and the smaller Prinses Irenebuurt became the last major residential developments in the southern part of the city. In 1961, the Amsterdam RAI Exhibition and Convention Centre opened, which was to become the largest convention centre in the Netherlands. The A10 motorway, which runs through the southern borough,