This is the Shanghai Bund Sightseeing Tunnel.
Part tourist attraction, part transportation. This connects the very popular Bund river walk with the Pudong area. It is the quickest way to get under the river and to the Oriental Pearl TV Tower, the aquarium, the Jin Mao Tower, an enormous shopping complex and many other tourist attractions. The Bund Sightseeing Tunnel is actually faster than taking the subway (because of the walk to the subway stations).
AloJapan.com