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.