The photo shared shows a picnic table covered with empty bottles and glasses. It has as its background a grey surface of some sorts. The picture asks people what that surface is - a wall or a river. "We cannot be certain. The longer you think, the less clear it is. What do you think?" says the Facebook post.
The picture has collected lots of comments on the social networking site.
"It is a river," says one commenter. "This is a wall because of the size of the leaves on it," says another.
What do you think it is - a wall or a water body? Tell us using the comments section below. Click for more trending news
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.