Interestingly, a number of buildings in the USA do not have 13th floor - 13 the unlucky number for Westerners.
I remember going to an office building in the Philippines and there was no 13th floor - not surprising given the influence of US on the Philippines.
Can read more about this from here:
(1)
http://boards.straightdope.com/sdmb/...d.php?t=610941
(Someone asked the question: "Do tall US buildings Not Have 13th Floor" and you can see the many responses to this question)
(2)
http://en.wikipedia.org/wiki/Thirteenth_floor
So don't try selling units on the 13th floor to Westerners!