On the opening day of the Nagano Winter Olympics, February 7, 1998, the five continents of the Olympic rings came together in a chorus of thousands to perform Ludwig von Beethoven’s Ninth.
As described in this post, this was a feat of technical amazingness.
Each chorus was miked and its performance relayed back to Japan individually with precisely the amount of delay required in each case to get the choral parts arriving simultaneously, where they were then blended with the (delayed) live performance in Japan. All of these parts were coordinated and re-broadcast to the whole world together.
May you all find joy, coming together across the seas and over the mountains, in harmony, as we bring 2015 to a close.