This afternoon, students attending Professor John Gaddis’ “Cold War” lecture witnessed history come to life. Literally.

Dressed in costumes ranging from President Ronald Reagan to Soviet leader Mikhail Gorbachev, the Yale Pundits, the Yale Precision Marching Band and the Yale Russian Chorus stormed Gaddis’ class this afternoon roughly 10 minutes into the Cold War historian’s lecture. After bursting onto the balcony and ground level of SSS 114, a Gorbachev impersonator delivered a grandiose speech in Russian while other students divided the room in half by stringing a curtain — representing the Berlin Wall — across the lecture hall.

The Russian Chorus then entered the room on one side, while two students — one dressed as a U.S. Air Force pilot — yelled at each other from the other side of the room.

“West Berlin is falling, we’re gonna need an air drop!” shouted the makeshift pilot as silver packets of Alpha Delta Pizza chips rained down from the balcony and onto the “free” side of the room.

The chips had barely stopped falling when Alex Kramer ’13 called across the room to Gorbachev and began to deliver Reagan’s famous speech at Brandenburg Gate, in which Reagan famously asked Gorbachev to “tear down this wall!”

“Mr. Gorbachev, open this gate!” Kramer called from the balcony, just as the Yale Precision Marching Band burst into the room blaring “The Star-Spangled Banner” and the Russian Chorus rushed down the wall.

As the curtain came down, pranksters on both sides briefly hugged and celebrated their brief liberation, then fled the room almost as quickly as they had come.

Gaddis, no doubt used to such disruptions — pranking his class has become an annual tradition — smiled as the dramatic scene unfolded.

“It’s a good thing they didn’t get champagne on the computer, or there would’ve been no lecture,” he quipped.

Correction: Wednesday, Nov. 28, 2012

An earlier version of this article mistakenly attributed part of the above events to the Yale Slavic Chorus. In fact, the pranksters were members of the Yale Russian Chorus.