The 'creeping black slime' taking over historic building around the world: Researchers reveal monuments from Washington to Angkor Wat now hit by impossible to remove biofilm
http://www.dailymail.co.uk/sciencetech/article-3755194/The-creeping-black-slime-taking-historic-building-world-Researchers-reveal-monuments-Washington-Angkor-Wat-hit-impossible-remove-biofilm.html