OPAS is your personal audioguide
Let's assume you were looking for an "mp3 audioguide" or, maybe, audioguida, or, even, audioguía. Then, OPAS is your choice! Why?
Because, this app offers hundreds of professionally written audio stories which will guide you through the city, playing automatically when you are in the proximity of interesting point. Not enough? This app offers hundreds of audio stories about exhibits in museums you are passing by. Still not enough? You can choose the language or languages in which you want to hear the stories and, very soon, the topics you want to hear stories about.
A truly personal guide on your mobile phone!