Here's what couples look like when they sleep-in surreal time-lapse photos

Paul Maria Schneggenburger has always been fascinated with sleep."It's an unconscious state of mind where scientists still haven't really figured out yet what's going on," he says.

Early in his career, Schneggenburger would take pictures of sleeping people where ever he saw them: "On the park bench, trains, at the party."

In 2010, he had the idea to take six-hour exposures of sleepers: first himself and then couples, families, and anyone else he could convince to come into his Vienna studio. Shot on black sheets in a dimly lit room, the images are intimate and surreal.

"The Sleep of the Beloved" is an ongoing series. Schneggenburger invites anyone who is interested to contact him about recording their own sleep.

Check out a selection below.