For pure architectural drama, the recently built Top of Tyrol observation deck in Austria ... even more vertiginous viewing platform at the Grand Canyon Skywalk, finished in 2007.

If you’re looking for an unforgettable adventure, one of these Grand Canyon train tours should be at the top of your list.

This full-day Grand Canyon tour run by Comedy on Deck Tours gives guests several options to customize their experience, such as a VIP Skywalk tour. But there is also a great base package.