In this second of two segments, learn about the alternatives to bottled water and what you can do to help protect our environment.

At times, Doc Gruber's research requires the team to dive right into shark-infested waters! Their line of work certainly isn't for the faint of heart! Enjoy.

All Hands Volunteers is a US-based, non-profit organization that provides hands-on assistance to survivors of natural disasters around the world with maximum impact and minimum bureaucracy. Their mission is to enable volunteers to provide assistance to communities affected by natural disasters.

Nathalie and Jim get up close and personal with tiger and lemon sharks, trying to get the best footage while taking care not to disturb or excite the dangerous animals.

WWF marine advocate Bob Zuur out at night on penguin patrol as part of the Oiled Wildlife Response team.

The world’s worst human rights abuses require permanent solutions. The Enough Project uses cutting-edge research, advocacy and campaigning to work toward ending genocide and crimes against humanity.

In a recent trip across the Sudanese border into rebel-held territory in Sudan’s Nuba Mountains, George Clooney witnessed rocket attacks and the effects of aerial bombardment by the Sudanese regime against the Nuban people. This trip diary was written and directed by George Clooney in the field with the Enough Project.

In this episode, Doc Gruber and a colleague are testing a shark repellent. If effective, it could help save the lives of divers, swimmers and surfers all over the world.

Rosetta revisits the exciting scientific discoveries she has made during her time at Comet 67P/Churyumov-Gerasimenko, including the successful search to find Philae. Now it's time to start preparing to descend to the comet for the end of her extraordinary mission.

WWF: Long-distance swimming puts polar bears at risk of drowning due to fatigue or rough seas. Cubs are at even greater risk because their smaller body size and limited body fat leaves them more prone to hypothermia, and they don’t have the energy reserves of an adult bear.

Ever wondered why most Americans don't like tea? Have they ever even tasted a cup of tea properly prepared? Simon Jones is convinced that they haven't and gives a nice detailed description, taken from "The Hitchhiker's Guide to the Galaxy," of how to make a proper cup of tea. Enjoy!

Here's some more stunning underwater footage. This time it's hammerhead sharks and stingrays, a wahoo and some striped eels, all filmed near the Cocos Island in the Caribbean. Take a look!

Over the last two decades, the environmental crisis of Florida’s Lake Okeechobee has continued to worsen and dominate local headlines. The lake is the nation’s second largest freshwater lake, but due to years of missteps, it’s been producing massive amounts of toxic algae that have closed beaches, destroyed businesses and poisoned swimmers.

In the war zones of Liberia and Congo, four volunteers with Médecins Sans Frontières (MSF) struggle to provide emergency medical care under extreme conditions. With different levels of experience, each volunteer must find their own way to face the challenges, the tough choices, and the limits of their idealism.

Samuel Gruber's team films white-tipped sharks and barracuda feeding at night off Cocos Island. Enjoy!