The Berlin Wall divided West and East Berlin for 28 years. Since German reunification in 1990, the city is finally whole again. Still, one of the best ways to explore the last traces of this Cold War past is to cycle or hike along the Berlin Wall Trail. The 160-kilometer tour is well signposted.

The tour can easily be started anywhere you want. An interesting place to begin is the Berlin Wall Memorial. Following the wall's former location on Bernauer Street, it shows how the border fortifications were set up and pays tribute to those who fled or died trying to escape East Berlin.

These cobblestones will help you recognize where the Berlin Wall once stood. However, only certain parts of the former frontier are marked out in this way. When the wall came down on November 9, 1989, East and West Germans were eager to get rid of all traces of it.

Following the Berlin Wall Trail toward the center of town, it will lead you to the government district, Spree River and the iconic Brandenburg Gate — which stood in a kind of no man's land when the city was still divided.

Checkpoint Charlie remains the most famous former crossing point between East and West Berlin. Tourists now stop there to snap a picture, under a replica sign reading: "You are leaving the American sector."

More than 300 watchtowers used to overlook the Berlin Wall, allowing East German border guards to catch people trying to flee. Only a few were left standing, such as this concrete structure near Potsdamer Platz, now listed as a historical monument.

Another classic attraction that can't be missed on the Berlin Wall Trail is the East Side Gallery. International artists painted an array of colorful murals on this 1.3-kilometer (0.8-mile) long stretch of the wall in 1990, making it one of the largest open-air galleries in the world. This depiction of Leonid Brezhnev and Erich Honecker kissing is one of its most famous murals.

The route continues through the city proper until it reaches the suburbs and finally Potsdam's Glienicke Bridge, where spies used to be exchanged in Cold War times. In 1962, a KGB agent and an American pilot were swapped at this very place. The story served as inspiration for Stephen Spielberg's 2015 movie "Bridge of Spies."

Large parts of the route pass through forested areas surrounding the city. Right on the bank of the Havel River, this watchtower in Hennigsdorf, about 20 kilometers (12.4 miles) northwest of Berlin, houses a small museum on the history of the frontier. It's free to visit.

Returning to the city, you'll be greeted by a cherry tree avenue in Pankow, which is most spectacular toward the end of April, when the trees are in full bloom. The Japanese donated some 10,000 trees "to bring peace in the hearts of the people." They were planted in different sections of the former wall. This avenue is right by Bösebrücke, the first crossing to open on the day the wall came down.

The Berlin Wall divided Berlin for 28 years, two months and 27 days, from August 1961 to November 1989. The Brandenburg Gate had long been the symbol of the division of Germany. Even after the fall of the Berlin Wall on November 9, 1989, there was no passage here. That changed on December 22, 1989. Since then, Berliners have been able to walk unhindered through the landmark of their city again.

The East Side Gallery on the River Spree in Friedrichshain is a 1.3-kilometer-long section of the so-called Hinterland Wall, which artists from all over the world painted in 1990. It was located in front of the death strip and a second wall. The area near the Oberbaumbrücke is a tourist attraction, but several wall elements have already been removed in the course of construction projects.

Nowhere is the former "death strip" as vivid as it is here. An 80-meter-long segment of the Wall, including a guard tower, has been reconstructed. The authentic border fortification complex serves as a central reminder of the division of Germany. It pays homage to the victims who died or were killed at the Berlin Wall.

The Berlin Wall has disappeared almost everywhere in the city. East and West have now grown together. A strip of cobblestones in the city center marks where the Wall used to run.

This border crossing is among the best-known sights in Berlin. Only foreigners and diplomats were allowed to pass through this checkpoint. In October 1961, shortly after the Wall was built, there was a standoff here as armed Soviet and American tanks stood face-to-face. The situation very nearly escalated.

It was a place of tearful farewells. Hundreds of people crossed this border post at Friedrichstrasse station when leaving East Germany for West Berlin. The former departure terminal now serves as a reminder of the forced separation of friends and families. Visitors can walk through an original cubicle where passports were checked and relive the border clearance procedure for themselves.

This former Stasi prison has been a memorial to the victims of communist dictatorship since 1994. Visitors are informed about the detention conditions and interrogation methods in communist East Germany. Former inmates lead the guided tours.

After World War II, this area was used to deposit debris. Rubble from the war was collected to form the Teufelsberg, the highest elevation in West Berlin. During the Cold War, the US National Security Agency used the hill as a listening station. From here, military radio signals from the Warsaw Pact countries could be intercepted, monitored and jammed.

You might imagine that the exchange of captured spies only took place on the silver screen, but this bridge between Berlin and Potsdam was actually the scene of three such operations. Steven Spielberg used this historic place as a setting in his feature film "Bridge of Spies."

This interactive museum right near Potsdamer Platz takes visitors into the world of espionage. Special emphasis is placed on activities in Berlin during the Cold War. Among the more than 300 exhibits is an East German Trabant car with infrared cameras hidden in its doors.

The Berlin Wall Trail follows the path of the former division of the city and covers some 160 kilometers. The Japanese donated some 10,000 cherry trees "to bring peace in the hearts of the people." They were planted in different sections of the former Wall. This avenue is right by Bösebrücke, the first crossing to open on the day the Wall came down.