The world's longest mosaic wall runs for 6.5 kilometers in Hanoi, Vietnam. The the Hanoi Mosaic Road is an artistic enhancement to the city's flood wall in which artists, government bodies from around the world, and corporations sponsored sections of art made from ceramic tiles. The mosaic was finished in 2010, and was certified as a record-holder by the Guinness Book.
Jürgen Horn and Mike Powell, who moved from Saigon to Hanoi, documented the different styles of mosaic art, which you can see at Hanoi for 91 Days.