Christian Marclay's "The Clock" is both the ultimate feature film and an artwork you can set your watch by.
The Swiss-American artist has edited together thousands of movie clips containing clocks, watches or references to the time — one or more for every minute of the day — into a 24-hour video.
It's a mesmerizing patchwork, full of sex, drama, action, excitement and hundreds of characters, that moves forward in time as it dances back and forth across film history.
First displayed in 2010, the piece goes on show this week at London's Tate Modern , which plans several all-night openings so that it can be shown in its entirety.
Marclay knows most visitors won't see the whole thing, and admitted Tuesday that he's never sat through the full 24 hours.