In what year was the 'Baku City Circuit' first used in Formula One racing?

The Baku City Circuit is a motor racing circuit in Baku, Azerbaijan constructed near Baku Boulevard. A lap of the circuit is 6.003 kilometres (3.730 mi), making it the second-longest circuit on the Formula One calendar. The inaugural Formula One race at the circuit was the 2016 European Grand Prix and its support events. A year later, in 2017, the circuit held the inaugural Azerbaijan Grand Prix.

The six kilometre, anti-clockwise layout of the circuit was designed by circuit architect Hermann Tilke. The circuit was planned to start adjacent to Azadliq Square, then loop around Government House before heading west along a 1 km straight to the Palace of the Shirvanshahs and Maiden Tower. Here, the track was planned to have a narrow 7.6 m (25 ft) uphill traversal and then circle the Old City before opening up onto a 2.2 km (1.4 mi) stretch along Neftchilar Avenue back to the start line. The circuit was projected to be the fastest street circuit in the world, with a top speed close to 360 km/h and the second longest circuit on the current F1 calendar behind the Circuit de Spa-Francorchamps in Belgium which currently is the longest circuit on calendar.