The subjects of Stone Age cave paintings thunder onto the screen as NOVA explores Woolly Mammoths. Recent discoveries show that the hairy ancestors of elephants fought off extinction much longer than anyone thought, surviving on an isolated island in the Arctic Ocean until as recently as 4,000 year ago.

NOVA investigates the myth and reality of the first known Europeans to reach North America -Vikings. These intrepid Norsemen explored and settled parts of present-day North America 500 years before Columbus set sail.

NOVA looks at the most successful life forms on the face of the planet in Ants: Little Creatures Who Run the World, hosted by Harvard University's internationally renowned ant authority, naturalist Edward O. Wilson. What's impressive about ants is how they practice what we preach: family values. Unselfishness is the rule. Everything they do is for their colony's good. For them, socialism works.

Born joined at the pelvis, Siamese twins Dao and Duan were brought to the United States from Thailand to assess their chances for being separated surgically. NOVA covers the intricate planning and protracted operations that eventually made the two girls into two distinct individuals.

Shortly after midnight on 17 July 19l8, at a house in the town of Ekaterinburg in the Ural mountains, Bolshevik guards awakened the deposed Tsar Nicholas II together with his family and forced them into the basement, where they were shot and clubbed to death. NOVA follows forensic tests of skeletons discovered in Ekaterinburg in 1979 that are alleged to be the remains of the Russian royals, and explores the intriguing claim that Anna Anderson of Charlottesville, Virginia, was really the long lost Anastasia.

NOVA unravels baffling cases of bad air in buildings all over the world. Even hospitals are on the "sick building" list - along with offices, schools, homes and just about any enclosed space.

What amazing processes go on inside super-athletes and couch potatoes alike? NOVA uses the latest medical imaging techniques to explore the body's incredible inner workings-with the help of Olympic ice skater Bonnie Blair, world record long jumper Mike Powell and others.

In the third installment of a 10-year project, NOVA checks up on a group of aspiring doctors who've been chronicled since their first day of medical school in 1987. Now bona fide MDs and in the middle of residency training, the group faces the awesome responsibility of curing the sick and keeping their own lives intact.

What does it take to win at Indy? NOVA follows champion race driver Bobby Rahal and a team of engineers as they strive to design a new car that can win the checkered flag at the Memorial Day classic. The program also features racing insights from top drivers Emerson Fittipladi, Willy T. Ribbs and Lyn Saint James.