Not many cemeteries would be listed among a city’s top 10 sights, but Arlington is an exception. Catch the ceremonial changing of the guard at the Tomb of the Unknown Soldier, where soldiers keep a 24-hour watch in honor of the unidentified dead from World War I, World War II, and the Korean War. Beyond the tomb, you can visit the graves of presidents, military leaders, and other notable figures, or take a quiet walk through the grounds.

Knez Mihailova Street is the pedestrian area that unifies Belgrade's beautiful architecture. It leads to the Belgrade Fortress and Kalemegdan Park on one end, and to Terazije and the iconic Terazijska česma drinking fountain near Hotel Moskva on the other, offering a splendid view of the Sava river valley. Inside tip: Take a detour to Kosančićev venac, the oldest part of Belgrade outside the fortress. This charming elbow-shaped street is home to Princess Ljubica's Residence, the Building of the Patriarchate of the Serbian Orthodox Church, and the Cathedral Church of St Michael the Archangel, all of which are sure to captivate you with their elegance.

The United States Holocaust Memorial Museum is a powerful and in-depth memorial and education center. Using artifacts, survivor testimonies, and films, the Permanent Exhibition traces events from the rise of the Nazis to the aftermath of the Holocaust. It’s a sobering experience that most visitors spend two to three hours exploring.