Built from 1914 and opened on December 17 and 19, 1916, the tunnel was used by the tramway as an underpass under the boulevard, replacing an at-grade crossing at the same location that had been put into operation in 1894.

The tramway used the structure until 1951, after which it was used as a prop warehouse for the Berlin State Opera and as a parking lot for vehicles of the East German People's Police.

In 1875, the GBPfE made a first attempt to cross the Linden via Charlottenstrasse, which was rejected by the Berlin Police Commissioner due to the narrow width of the street.

Since the central north-south connection was still missing, the management of the horse-drawn railway, with the support of the Berlin magistrate, approached the police authorities again in 1885.

There were further negotiations about the location of the intersection; the parties agreed on a connection at the level of Hinter der Katholischen Kirche, Platz am Opernhause[A 1] and Kastanienwäldchen (between the Palais des Prinzen Heinrich, Neue Wache and Sing-Akademie[A 2]).

This type of power supply was not satisfactory, as the cable ducts quickly became clogged with leaves and slush, and the pantographs broke off at the slightest obstacle.

Due to the enormous width of the roadway, the cables were stretched over a length of 60 meters at street level without intermediate suspension.

[4] Alternatively, the emperor is said to have uttered the phrase " Under, not over",[1][3][5] which, according to other sources, was also intended for the construction of a suspension railway based on the Wuppertal model.

In 1900, the city decided to build its own tram lines, and both sides drew up different plans[4] for the Lindenkreuzung intersection, including a tunnel under the street at the Opera House.

At the same time, GBS expanded its plans and, together with its subsidiary Berlin-Charlottenburg Tramway, presented an extensive system of tunnel routes in 1905.

The 1907 version of the northern tunnel included two loops under the Platz der Oper and the Brandenburg Gate to accommodate north-south traffic.

The city administration, however, did not back down from its criticism, relying on the findings of several experts, including Gustav Kemmann and Otto Blum.

City planning officer Friedrich Krause countered the GBS design with a memorandum proposing several short tunnels instead of two long ones, including at the Opera and the Brandenburg Gate, as well as numerous street breakthroughs.

In an audience with the Kaiser, the mayor of Berlin, Martin Kirschner, finally decided that the northern tunnel - with the exception of the north-south crossings - was unnecessary.

The city extended its franchise until December 31, 1939, and granted the company additional rights with respect to the streets to be used and the fare structure.

The city itself was most interested in a rapid completion of the Lindentunnel in order to connect its own lines, which terminate north and south of the tunnel.

In order not to overload Französische Strasse, a four-track tunnel was planned with two separate southern ramps on either side of the opera house.

[3] In February 1914, Kaiser Wilhelm II issued a building permit for the project, which was submitted to the Berlin City Council for approval on April 17, 1914.

[11] This was not possible in the west tunnel, however, because the project was awarded on the condition that the monument to Empress Augusta, which would pass underneath, would remain in place.

[10] Due to the steep incline of the ramps and the limited field of view caused by the curves in the track, several safety systems were in place: All in all, these measures meant that there were no serious disruptions to regular operations.

Before the tunnel was built, the tracks ran in a straight line from the bridge via Am Festungsgraben and Hinter dem Gießhaus to Lindenkreuzung.

To prevent parts of the building from sinking, the tension pressing the planks against the ground was increased by arched plates riveted between iron posts.

In early February 1915, work began on lowering the groundwater level; pumps were set up every five to six meters to drain the water into the nearby River Spree.

In addition to the actual track bed, this included the aforementioned centrifugal pumps, tunnel lighting, ramp railings and integrated catenary masts, as well as the signaling system required by the supervisory authority.

[18] In 1926, as part of the redesign of Kaiser-Franz-Joseph-Platz for the extension of the Opera House, the tunnel was closed off with a retaining wall, the ramps were filled in, and the area was leveled.

The Berliner Zeitung reported that line 46 (Nordend - Dönhoffplatz) would begin using the tunnel again on May 26, 1950, one day after the opening of the first German Youth Festival.

[14] In a separate room at the end of the west tunnel, there was a switchboard for the People's Police operational television, which was used by the Ministry for State Security and others to monitor important points in East Berlin.

However, the construction of a memorial to the 1933 book burning in Germany in the area of the southern ramp in the middle of Bebelplatz changed these plans.

[23] The southern access road on the west side of Unter den Linden was partially uncovered and an information board was installed.

[25] Since September 2002, the Maxim Gorki Theater has been using an approximately 80-meter-long section of the tunnel from the north ramp as a scenery storage area.