This is akin to referring to the United Kingdom as England. Holland is only one district of The Netherlands. It is correct to say that you’re traveling to Holland if you are visiting Amsterdam, due to the fact that Holland (which means woodland) refers to the northern region of the country. The other regions of The Netherlands generally dislike being referred to as Holland (because they’re not Holland), but since the Holland region was a central part of the country’s economic history, and therefore more widely known on the global stage, many people refer to the country as Holland. The bottom line, however, is that it’s wrong. The country is called The Netherlands and Holland is one of several districts.