Some lovers of classical music consider the second movement of Beethoven's Seventh Symphony to be one of the most beautiful pieces ever written.
See it performed, in this clip, by the Berlin Philharmonic (under the direction of Herbert Von Karajan who never looks at a score and keeps his eyes shut throughout).
The second movement begins at about 11:18 in this video clip. Move the video forward to hear it.
Karajan recorded his Beethoven Symphonies (for Deutsche Grammophon) between 1968 and 1973. This recording, of the 7th, was made in 1972.
NPR provides more information about the 7th Symphony and its second movement:
The Seventh Symphony's premiere concert [on December 8, 1813] was performed to benefit the soldiers wounded a few months earlier in the battle of Hanau. It was one of Beethoven's most successful concerts.
Viennese audiences, miserable from Napoleon's 1805 and 1809 occupations of Vienna and hopefully awaiting a victory over him, embraced the symphony's energy and beauty.
Even today, the second movement remains extremely popular and is often performed separately. The NPR history and analysis continues:
Occasionally, Beethoven wrote something that was immediately recognized as both artistically great and hugely popular. An example is the second movement of his Seventh Symphony, a piece that was often performed separately from the complete Symphony and that may have been Beethoven's most popular orchestral composition. It also exerted extraordinary influence on later composers, as the slow movements of Schubert's "Great" C-major Symphony and E-flat Piano Trio, Mendelssohn's "Italian" Symphony, Berlioz's Harold in Italy, and other works attest.
After its premiere, the Seventh Symphony was repeated three times in the following 10 weeks; at one of the performances the "applause rose to the point of ecstasy," according to a newspaper account.
Clip from Karajan - Beethoven - The Symphonies. Online, via YouTube.
Quoted passage, regarding the 7th Symphony, from NPR.