>><snip>
>>it would be a good surprise for her on Thursday (tomorrow is a Labor day).
>>>
>>Hi Nadya,
>>I always think that Labor day is 1 May, and it comes from americans
>
>I understand 1 May is Labor Day in most countries in the World (here we know it as Día Internacional del Trabajo, International Labor Day) - but not in the U.S., which is where the events of 1 May occured. The reason may be related to the fact that these events are shameful for the U.S., but I am not sure.
>
>Hilmar.

Possibly due to that big US fear : communism

The Socialist Party held a similar celebration of the working class on May 1. This date eventually became known as May Day, and was celebrated by Socialists and Communists in commemoration of the working man. In the U.S., the first Monday in September was selected to reject any identification with Communism.
http://wilstar.com/holidays/laborday.htm

Here's another view :
http://www.cs.uni.edu/~campbell/gened/labour.html