Try to find the scyscrapers hidden in the grid. The buildings are of various heights (1<2<3...). Each scyscraper appears only once in every row and column. The numbers around the grid tell you how many buildings you can see fom that vantage point in the corresponding row or column. - Keep in mind that higher buildings hide smaller ones. If there is no number above or below a column or beside a row, that doesn't mean anything, there is just no more information.

Other names for that kind of puzzle are Skyscrapers, Urban Landscapes or Gratte-ciel.

In this little example you have to find the skyscrapers 1, 2 and 3. The two hints outside the grid give you enough information to find out where all the skyscrapers are hidden. The number 3 tells you, that in this column all three buildings are visible, therefore you have to enter 1-2-3 from top to bottom. The number 1 on the top right corner tells you that only one building is visible in this row from that vantage point. Therefore there must be a 3 in the top right corner. Now as we have already discovered four houses, the rest will be found easily.

There are some variants of this puzzle, for example:

• In addition to the houses there can also be empty squares in the rows and columns. Of course they can't hide any houses, but they make the puzzle a bit more complicated. For example now the hint "1" doesn't mean definitely that the highest building is the the first one, there can also be an empty square in the first cell and the highest building in the second one.
• In another variant you also have to pay attention to the diagonals. Each letter and each square (if there is one) appear only once in each diagonal.