2. Living on the Edge

The teams face some steep terrain, and high altitude takes its toll on a number of the challengers.

3. Leave No Man Behind

Bear challenges the teams to swim to shore from the middle of a bay and navigate waterfalls.

4. The Mountains Will Give You Strength

A helicopter takes the remaining teams to the base of a raging waterfall, which they must ascend.

5. Don't Look Down

The remaining contestants must cross a rope suspended 100 feet over a gorge.

6. The Tough Get Going

The teams face the coldest night yet, and they must join forces to rappel down a cliff.

7. Frozen Planet

The four remaining teams must navigate the dangerous terrain on top of a glacier.

8. No Guts, No Glory

Drenched but determined to win, the remaining teams work on their own to show what they've learned.