With her two cubs huddled close and asleep, mama polar bear takes a moment to nap herself, in this irresistibly cozy photo from Tom and Pat Leeson. These Sierra Club holiday cards are imprinted with the message "Season's Greetings" inside. The clear-lidded box contains 12 cards, all of the same subject (measuring just under 5 x 7 inches), with 13 white envelopes.