Building is giant crossword puzzle
"As night falls, puzzler enthusiasts gather outside a residential block in Ukraine in an attempt to decipher the world largest crossword.But unlike your newspaper variety, this puzzle is more than 100ft high and fills the entire external wall of a tall building in the historic city of Lvov.
Clues to the massive puzzle, which is 19 squares across and 34 squares high, have been scattered around the city's major landmarks and attractions including parks, fountains, and theatres.
[...]
The brainteaser is too big to be penned by hand, so fluorescent letters are placed inside every square and turned on at night revealing the complete solution."
http://www.dailymail.co.uk/news/worldnews/article-1119722/The-worlds-largest-crossword-puzzle-built-100ft-tower-block-Ukraine.html