Few months ago, I was talking to Siva. He is part of Tamil Heritage Activities. They take people to Mahabalipuram often and explain all its great history.
They are looking for a mobile app to auto explain about the nearby place, by getting the geolocation of the person.
if you goto near to tiger cave of mahabalipuram, the app should explain all about tiger cave. The data can be provided from a wikipedia page or some custom webservice.
We can extend the same to any place. Like, extending the same for all the temples in kanchipuram or even all over world.
Wikipedia and wikidata can be great starting points for providing required information.
Now, we are looking for android/ios developers to develop this as an open source mobile application.
If you are interested in this, mail me on tshrinivasan@gmail.com or reply here.
Thanks.
Going GNU 
wikimapia.org ?
the app will be immensely useful!