The V-1 (V standing for Vergeltungswaffe, or “Vengeance Weapon”) a.k.a. the Fieseler Fi 103, was the world’s first operational cruise missile. It was inaccurate and unreliable, but cost dramatically less to build than a V-2 and carried the same one-ton high-explosive warhead. Between June 1944 and March 1945, over twenty thousand V-1s were launched at the allies, primarily at London and Antwerp.
The V-1 was powered by a pulse-jet engine, cycling 45 times a second. The resulting cyclic slap of the intake shutters led to the V-1 being nicknamed “buzz bombs” after the loud sputtering sound they made in flight.
Given the number of partially-completed V-1 missiles that were captured by the end of WWII, it’s no surprise that you’ll run into them at a number of Air and Space museums wherever you travel (Wikipedia has an excellent listing of them, BTW). Here’s one (# 121536) at the Pima Air Museum in Tucson, Arizona:
And here’s one at the Deutsches Museum in Munich:
And of course, you can also find post-war allied variants of the V-1 — like this JB-2 “Loon” at the National Air and Space Museum’s Udvar-Hazy Center in Chantilly, Virginia: