What is Tourism?

I just suddenly ask my self, what tourism is? This question brought me to my past time, where I studied tourism in the Udayana University, Denpasar Bali, 9 years ago.

Is there any revision on the terminology of tourism? Does the term/definition grow? Check these out...

Tourism is smokeless industry
Tourism is hospitality industry
Tourism is invisible export
Tourism is service industry
Tourism is multi-sector industry
Tourism is multi-S industry (sun, sea, sand, service, and smile...)
Tourism is recreation, leisure and pleasure
Tourism is lodging industry
Tourism is a mass employer
Tourism is everyone's business
Tourism is market friendly business
Tourism is state-income earner
Tourism is the fastest growing industry
Tourism is a beautiful-attractive girl

The meaning above, are based on industry or commerce or business perspective, most of them are with word "industry", so it more to do with business. What if with the meanings, below:

Tourism is peacemaker
Tourism is cultural heritage
Tourism is peace ambassador
Tourism is Museums
Tourism is ecology preservation
Tourism is socio-cultural phenomenon
Tourism is friendship
Tourism is understanding primitive traditions
Tourism is about local genuine

Those meanings are from conservatives who enjoy tourism. But what about the other meanings, such as...

Tourism is cultural exploitation
Tourism is custom and moral degradation
Tourism is about environment destruction
Tourism is a package of modernism, globalism and capitalism
Toursim is legalized prostitution
Tourism is multi-S, (sex, sex, sex and sex...)
Tourism is children sexual exploitation
Tourism is a new kind of mass desctructive weapon
Tourism kills tourism

You might think different. Would you contribute with your own perspective?