I think the largo, (second movement), of Dvorak's New World Symphony is one of the most beautiful and memorable melodies in the classical repertoire. Apparently other's have felt this way too, as I demonstrate below. Dvorak completed the work in the United States in 1893. It's formal title is Symphony No. 9 in E minor, "From the New World", Op. 95, B. 178.
Firstly you can listen to an extract from second movement played by the Dublin Philharmonic here.
Then, my very favourite, the spiritual song "Going Home", which borrows the melody, sung here by the stunning Norwegian soprano Sissel.
Now a song from 1968 by the Scottish group A New Generation (who later became The Sullivan Brothers). Their song, which faithfully reproduces the opening chords from Dvorak is called "Smokey Blues Away". Click here to listen.