Use this tag for the Aqua and Aria manga series, as well as all the Aria anime series.
Aria is a science fiction and slice-of-life manga by Kozue Amano. It is set in Neo-Venezia (a copy of Venice) on Aqua (a terraformed Mars) in the 24th century. It follows three young gondoliers as they explore the world around them, all the while training to be promoted to Undine rank.
Use this tag for both the Aqua and Aria manga series, as well as all of the anime series: Aria the Animation, Aria the Natural, Aria the OVA: Arietta, Aria the Origination, and Aria the Avvenire.
For more information, see Aria on Wikipedia.