Remember Robin Williams playing Sgt. Adrian Cronauer in "Good Morning Vietnam?" He was on was the American Forces Radio Network, stations set up by the U.S. government for soldiers stationed overseas to get a taste of home. During the 60s, these were often clones of American Top 40 formats, complete with jingles and disc jockeys. 

Those days are gone but the radio stations live on. The AFN has a website where military types can now tune in the stations wherever they are in the world over the web, provided they're in the right geographic area. But if you have a VPN that can choose a country to connect to, you can listen in, as well. Otherwise they're completely geoblocked, even to those in the U.S. 

I've always been kind of sorry we never got to hear those Top 40 broadcasts, although I'm certainly glad not to have ever been in Vietnam during that conflict. But if you're interested in hearing what they sound like today, you can adjust your VPN and check out the stations (which all seem to be called "The Eagle" for obvious reasons) at the links below. Many seem to be playing the exact same thing, as if being fed out of a central source, although the ones in Europe were different than the ones in Japan. 

There are links to stations in Benelux, Bavaria, Bahrain, Naples, Italy, Stuttgart, Germany, Okinawa and Tokyo, Japan, among others. I couldn't connect to what might be the most interesting one of them all - Guantanamo Bay, Cuba, where the U.S. base (and prison) remains, because there's no VPN connection for that country. But you have to wonder what they're listening to down there.  

You can try for yourself here:

AFN Europe

AFN Pacific