Drivers in downtown Moscow squinted in disbelief as an electronic highway billboard blazed a two-minute pornographic video instead of its regular advertising clips.
Late-night traffic on one of the Russian capital's busiest roads slowed Thursday as a couple's explicit escapades appeared on the 9m by 6m display.
Some people took pictures of the sight with their mobile phones and posted them on the Internet.
Passer-by Alyona Prokulatova she was "so shocked that I couldn't even shoot video or take a picture of it."
The screen's owner, 3 Stars, told the AP that a hacker attack was likely to blame. Police were investigating the incident.