This clip is from Schumann's "Traumerei" (Dreaming), which was played as an encore during the concert Vladimir Horowitz performed at the Great Hall of Moscow Conservatory in Moscow in April 1986.
On Sunday, April 20, 1986, Vladimir Horowitz, aged 82, held a concert in Moscow. The Russian-born pianist had left Russia in 1925, and this was his triumphant return after an absence of 60 years. There were less than 400 seats offered to the public, compared to 1,400 reserved for the Soviet VIP.
His reasons for coming to Russia were two-fold. Mr. Horowitz pointed out: to see Russia once more before his death, and to act as an ambassador to peace. [Mr. Horowitz died on November 05, 1989.]
On the day of the recital, people stood outside the concert hall in the rain even though they couldn't hear anything. Hundreds of students broke through security to watch the concert from the balcony, and guards couldn't manage to remove them.
To say the event was emotional is an understatement of the greatest order. I remember seeing the performance on television, and yes, there were tears in my eyes. Here are some additional notes about this concert from Wikipedia:
In the new atmosphere of communication and understanding between the USSR and the USA, these concerts were seen as events of some political, as well as musical, significance. The Moscow concert, which was internationally televised, was released on a compact disc entitled Horowitz in Moscow, which reigned at the top of Billboard's Classical music charts for over a year. Tickets for the concert were largely reserved for the Soviet elite and few music students were allowed to attend. This resulted in a number of Russian music students crashing the concert, which is audible near the end of the second track. The concert was also released on VHS, and eventually on DVD.