The world's heaviest poster is on a 6-ton rock in a New York park. It was part of a campaign by Guinness World Records to demonstrate that records are all around you, just waiting to be set.
http://adage.com/article/creativity-pick-of-the-day/guinness-world-records-campaign-breaks-lots-records/241737/
http://adage.com/article/creativity-pick-of-the-day/guinness-world-records-campaign-breaks-lots-records/241737/
