Blanka tunnel complex  Blanka Tunnel Complex is a part of the inner Prague City Ring Road. It is the longest road tunnel in the Czech Republic and the longest city tunnel in Europe. The complex connects the area west of Prague Castle with Trója district in the northeast. Its length is about 5.5 km and consists of three tunnels: "Bubenečský, Dejvický" and "Brusnický". The tunnel complex was designed to relieve the historic center of Prague from heavy traffic. During the construction there were three landfalls, two times in the Stromovka park, which created a hole on the ground of the park, with a diameter of 15 to 25 meters, and once at garden area of the Ministry of Culture in Hradčany. The incident was investigated by the police and damages were estimated at tens of millions of CZK. The construction of the Blanka tunnel was launched back in 2006 by then mayor of Prague Pavel Bém, although it was planned since 1993. The tunnel cost tax payers some 43 billion crowns (2015), much more than the originally announced 21.2 billion. However, this price doesn't include all construction costs. Initially due to open in 2011, the biggest and most expensive project in the history of Prague was repeatedly delayed. The tunnel was officially opened to the public on 19 September 2015. The building permit from 2004 set a condition that the tunnel must not be put into full operation, until the north-eastern part of the outside beltway (Prague Ring) was completed. However, this condition is not met, and as supposed, it will not be completed before 2028. That's why Blanka Tunnel was not officially approved. The authorities circumvented the condition in such a way that the tunnel is formally only in probationary operation, but for more than 10 years.