Mind Your Step Illusion By Erik Johansson, Sergel's Square, Stockholm, Sweden

A sunken pedestrian plaza furnished with a triangular pattern (colloquially referred to as Plattan, "The Slab") and a wide flight of stairs leading up to the pedestrian street Drottninggatan, connecting south to Stockholm Old Town and north to Kungsgatan.
This plaza is partly overbuilt by a roundabout centred on a glass obelisk and by the concrete decks of three major streets.
North of this traffic junction is a considerably smaller open space overlooked by the high-rise façade of the fifth Hötorget Building from where the avenue Sveavägen extends north.
The site south of the square is taken up by the cultural centre Kulturhuset, which also harbours the Stockholm City Theatre and hides the Bank of Sweden headquarters facing the square Brunkebergstorg behind. Klarabergsgatan leads west past the department store Åhléns City and Klara Church to Klarabergsviadukten and Kungsholmen. Hamngatan leads east under Malmskillnadsgatan to Kungsträdgården, Norrmalmstorg, and Strandvägen. Together with the underground mall east of the pedestrian plaza and the T-Centralen metro station and other continuous underpasses west thereof, Sergels torg forms part of a continuous underground structure almost a kilometre in length.