Unter den Linden is one of the preeminent avenues in front of Brandenburg Gate in the central district of Berlin. At the command of Johann Georg in 1573, it began as a pageant connecting the Stadtschloss royal palace to Tiergarten. In order to rebuild the devastated streets shortly after the Thirty Years' War, Friedrich Wihelm redesigned the streets by planting foreign plants that had been screened overseas together. After defeating Napoleon in the 19th century, the opera house designed by Karl Fredrich Schinkel entered the street, making it a wider and more well-managed road. By the end of the 19th century, embassies, apartments and shops for the middle class were built, Unter den Linden became one of the main roads in Berlin. Walking along this avenue from the Brandenburg Gate to Alexanderplatz over the Schloßbrücke from which it is called Karl-Liebknecht-Straße, many of Berlin's major sights are within a distance of 2 kilometers.1 The streets were completely destroyed after the two World Wars. In the process of rebuilding the post-war Unterden Linden in 1925, a proposal from Dutch architect C. van Eesteren2 was adopted to reorganize the road and maintain its appearance to this day.
Unter den Linden is the oldest example of the roadside tree streets that were planted with certain reason after being demolished several times. It reflects many countries’ streets such as Las Ramblas in Barcelona, Spain and Jacaranda trees in Johannesburg, South Africa. Las Ramblas was first designed in 1703 by planting birch trees. In 1859, it was replaced by platanus x acerifolia trees. Johannesburg is famous for the jacaranda trees throughout the city. J.D. Clark, who was a successful businessman, donated 200 jacaranda trees to Koch streets in Pretoria. And Frank Walter Jameson contributed to planting trees not only in Pretoria but also in Kimberly and Johannesburg. Now Johannesburg has 37,000 jacaranda trees along the city streets and in the outskirts of the city, it reaches 65,000 trees.