THE puzzle is more than 100ft high and fills the entire external wall of the residential building in the city of Lvov. Clues to the crossword are scattered around the city's major landmarks and attractions including parks, fountains, and theatres. Visitors are encouraged to collect and decipher all the clues during their weekend strolls, giving them a chance to exercise their brains as well as their legs. Although the crossword - which is 19 squares across and 34 squares high - is far too big to be filled in by hand, the artists responsible have come up with an intriguing way of displaying the answers. When night falls, fluorescent letters placed inside every square are turned on, revealing the complete solution in a light glow. It is hoped that puzzlers will gather outside the tower block every night to see if their own answers were correct. The huge crossword was created in an effort to attract tourists to the city, but British crossword enthusiasts should think twice before booking flights to Ukraine, as all the letters are from the Cyrillic alphabet. " Daily Telegraph