Kate Upton graces the cover of Sports Illustrated's annual swimsuit issue, barely suited up in Antarctica's early spring weather of about 24 degrees Fahrenheit. (With wind chill, it felt like minus 20 degrees).

Upton doesn't show any signs of goose bumps in the pictures. She no doubt got the chilliest assignment of the 17 models who posed for this year's swimsuit issue on seven continents.

READ: Kate Upton graces the cover of Sports Illustrated for the second time

Those logistics are the work of Sports Illustrated's senior editor for the swimsuit issue, MJ Day, and her team, who spend most of the year on the road shooting. For this year's 50th annual issue, years of negotiating visas and access paid off in shots on each of the world's seven continents. (Sports Illustrated, like CNN, is a division of Time Warner.)

Antarctica was "the 'Hail Mary' pass of our year," said Day, using perhaps the only sports metaphor applicable to the issue, on newsstands Feb. 12. "I could have had a blizzard. Kate could have had shivering fits you could not shoot around. (Instead) we had six days of perfect weather."

Day packed coats and wool socks for that trip in addition to the items more typically in her travel bags: Some 500 to 800 bathing suits, double stick tape, clothespins, safety pins, binder clips, liners from the cups of bathing suits (for use as knee pads), suntan lotion, bug spray and flip-flops.

While Day is a veteran road warrior traveling to many places most people will never see, even she was taken by her adventures this past year. Here are Day's favorite spots from her year's travels on each of the continents.

Antarctica: Kodak Alley

The Sports Illustrated team traveled to Antarctica in early December (early spring on the frozen continent) on the Abercrombie & Kent ship Le Boreal, enjoying a rare "six-day stretch of perfect weather" on the journey from Tierra del Fuego.

"Antarctica was my favorite place on Earth," said Day. "I'm one of the most jaded travelers you will ever meet, but the whole thing was a religious experience. Spend your money. It's worth it."

On the journey, they crossed a channel called Kodak Alley, where twilight arrived around midnight. "The sun sets in a shade of orange and mountains turn pink -- not a hint of pink, but as if someone poured pink paint over the mountains. You can't sleep because it's too awe-inspiring. Sleeping is not important. Seeing this is."

The photographer could only shoot Upton outside for a couple of minutes at a time before the crew, all bundled from head to toe, would rush to put heating pads in her bathing suit and cover her with electric warming coats.

"The entire crew surprised her the last day of her (six-day) shoot wearing bathing suits as a sign of support and thanks," said Day. "I was probably in my suit for five minutes and went so numb."

Africa: Wolwedans, NamibRand Nature Reserve, Namibia

Wolwedans is a group of lodges and camps that are part of the privately held NamibRand Nature Reserve in the southwest Namib Desert.

"I've been to sandy places such as Tunisia and the Sahara and seen those endless dunes, but the dunes here were the most intense shade of red I've ever seen in my life," said Day. "The sand in Namibia has such a high iron content. As the iron oxidizes, the redder it becomes. The further inland you go, the redder the sand gets: white to orange to insane red."

The Wolwedans runs on solar power, which means no sounds of generators to disturb the natural beauty. The lodge grows some of its own food and runs in partnership with a culinary school, "so the food is incredible, really wholesome, delicious and natural. You feel like 'I'm living and I'm living right.'"

"The level of quiet you experience is surreal. This is the perfect place to go to when you need to rest your soul."

Asia: Dragon's Backbone Rice Terraces, China

It took more than two years to negotiate the visas to get into China to shoot, and Day wasn't sure it would ever happen.

The shoot came to life at Dragon's Backbone Rice Terraces, an 800-year-old terraced rice paddy built into the mountains in Guangxi Province.

"It's the most ethereal, beautiful, surprising place on Earth to me," said Day. "These incredibly distinctive mountains were like what kids draw, up and down and up down. They were incredibly green, rich, lush and misty in the mornings."

The hike is so strenuous up the mountain stairs that many visitors hire the local Yao women to act as guides. The women of the Yao ethnic minority group, who are known for their brightly colored clothing and long hair styled atop their heads, helped the crew haul equipment for the shoots at the bottom and top of the hike, and at points along the way.

Australia: Whitehaven Beach, Whitsunday Island

It takes a lot for a beach to impress Day, who is not impressed by the backdrop that most beaches have to offer a photo shoot.