When in Rome, visit the Colosseum. It’s a no-brainer to stop at the iconic amphitheater when traveling across Italy, but the nearly 2,000 year old structure is anything but overrated. Considered one of the greatest Roman works of engineering, the stadium not only hosted gladiatorial fights but dramas and battle re-enactments as well. The amphitheater also served as what is likely the oldest recycling project of all time. Throughout the millennia following the Colosseum’s heyday, the structure was re-purposed as a church, a medieval apartment complex, a burial ground, and even a castle. Now, of course, it mainly serves as a tourist destination and a backdrop for high profile concerts.

Want to learn more?

Visit the Colosseum in Rome with Explorica.

Think the New York skyline is breathtaking? Take a look at Shanghai. Home to the largest population and the largest building in China, Shanghai takes the idea of a bustling, modern city to the next level. With its modern architecture, giant globes and iconic Oriental Pearl Tower, Shanghai looks more like a set from Star Trek than an actual city of earthlings!

Want to go here? Check out our Shanghai tours.

You haven’t lived until you’ve seen the Iguazu Falls up close and personal in Argentina. Visit the Iguazu Falls in Argentina.

For Earth Day 2013, make a resolution to learn more about green innovations across the world.