First this:

Billboard that looks like it's fallen, shattering its glass. Ad reads "OOPS"

Then the advertiser, a mobile phone insurance company offering ‘free’ screen replacements, did this follow-up (the front page is translucent):

A stupendous example of how to leverage innovative outdoor campaigns. Call us with your brilliant idea, or to brainstorm or to brief us. 9328 7844.

Campaign by VCCP London. More detail in Campaign.