Unter den Linden (ˈʊntɐ deːn ˈlɪndn̩, "under the linden trees") is a boulevard in the central Mitte district of Berlin, Germany. Running from the Spree River to the Brandenburg Gate, it is named after the linden trees (known as lime in England and Ireland, not related to citrus lime) that line the grassed pedestrian mall on the median and the two broad carriageways. The avenue links numerous Berlin sights, landmarks and rivers for sightseeing.
Unter den Linden runs east–west from the Berlin Palace, the former main residence of the royal House of Hohenzollern, reconstructed (after the demolition of the communist Palace of the Republic) on its old site opposite the Lustgarten park, to Pariser Platz and Brandenburg Gate. Major north–south streets crossing Unter den Linden are Friedrichstraße and Wilhelmstrasse, both meeting at Mehringplatz and running across the Friedrichstadt, a city expansion founded in 1691.
Eastward the boulevard crosses the Spree river, slightly kinked due to the oblique position of the long side of the palace compared to the boulevard, at the Lustgarten with Berlin Cathedral, and continues as Karl-Liebknecht-Straße, itself continued as Prenzlauer Allee, to the northern outskirts. The western, dead straight continuation behind Brandenburg Gate is the Straße des 17. Juni (formerly Charlottenburger Chaussee), which in turn is extended to the west by the straight sequence of Bismarckstrasse and Kaiserdamm, an axis, widened in 1904, that runs from Berlin Palace more than 10 kilometers across the city to the western outskirts where, slightly elevated, one can survey the length of the axis. The extension of the Linden alley to this gigantic axis was inspired by the Boulevards of Paris. The Kurfürstendamm, the magnificent shopping mile in the historically elegant west of Berlin, was similarly inspired.
Unter den Linden, which sits at the heart of the historic section of Berlin, developed from a bridle path laid out by Elector John George of Brandenburg in the 16th century to reach his hunting grounds in the Tiergarten from his palace.