The Denver Aquarium is loads of fun, what with sunken temples, re-created flash floods and piranha tanks, but it's also pricey. Between parking fees, multiple gift shops and added activity charges ...

The best ways to get around Denver are on foot or by light rail ... passing such sights as the Downtown Aquarium and Elitch Gardens Theme Park. Single rides cost $5 for adults and $2 for children.

The instant I surfaced from the cold, salty water of the Downtown Aquarium in Denver, though, I was drumming up ways to fund a tropical scuba vacation. “Once you get people in the water ...