673 Visiting Antarctica; Journeys of Trees; Italy's Northern Lakes

Travel writer Julian Sancton tells us how a trip to Antarctica helped him see that continent through the eyes of the early polar explorers. Then science reporter Zach St. George explains how some North American tree species are migrating to survive a warming climate. And two Italy-based tour guides take us to the resort lakes of northern Italy, where outdoor sports and celebrities compete with the scenery for visitors' attention.