The ice plains biome is filled with massive ravines; however, getting to the bottom of one safely is another story. Head east from the spawn point to locate the closest one (coordinates: 85, 25). Be sure to grab some coal and wood along the way.
You can create a safe and easy travel route by placing torches near the frozen lake to melt the ice. Then, remove the dirt to allow the water to flow into the ravine. Voila!
Ravine environments are not without their challenges. Enemies swarm the dark tunnel networks, but defeating them leads to high payoffs. Coal, iron, gold, lapis lazuli, and redstone are all in abundance -- be sure to mine them before leaving.
You'll probably want to bring spare torches along for the journey, too (and some friends who haven't discovered the sprint function).