Some couples like to pose for a picture when visiting Sugarloaf Mountain. Others would prefer to don a helmet, grab some rope, and rappel down its rocky faces. Couples seeking a thrill will find plenty of opportunities for an action-packed date in Rio. You can take a helicopter ride to the top of Christ the Redeemer, explore the caves of a nearby rain forest, or hang glide off the mountains that tower above the city. For a more laid-back adventure, rent a sailboat and cruise around the islands of the glistening Guanabara Bay. Ask the captain to time your return with the sunset. You won't regret it.