If the options for your next vacation came down to the standard beachside getaway or a spa trip inside of a Romanian salt mine, which would you choose?

Should an ancient mine sound more appealing than sipping margaritas in the Caribbean, you’re not alone. Travel experts say more of today’s travelers are looking for vacations that are unique, exciting and even a little bizarre.

Since 2009, has accelerated by 65 percent year over year, according to a study by , and the market was valued at more than $260 billion last year.

For photos of locales you likely won't see on your friend's Facebook page, scroll through our slideshow above.

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