The final presidential debate is not just hoping from country to country: the two candidates are also time-traveling in their references.
Obama came out with the first zinger of the night when he was critiquing Romney's view of the biggest national security threats facing America.
"The 1980s are now calling for their foreign policy back," Obama said of the GOP candidate's earlier assertion that Russia posed the biggest geopolitical risk to the US, as CNN reported.
The conversation then jumped back to the 1900s: Obama attacked Romney’s view of America's shrinking military as dated, saying “We also have fewer horses and bayonets" in response to Romney's comments about the US forces needing more funding and more equipment.
The Daily Beast quipped that "Horses and Bayonets" was "an undeniably awesome band name idea, and Obama’s best zinger in the first half of the presidential debate."
Here, some more clever comments on the historical references in the debate so far: