Challenges in 2021: Walter Isaacson / Author, Professor of American History and Values at Tulane University

Cameras film around the clock in some of Britain's busiest A&E departments, where stories of life, love and loss unfold every day

Led by Emmy Award-winning journalist Paula Zahn, On the Case features in-depth interviews and original reporting that go beyond the headlines in search of fascinating mysteries from within our nation's justice system. Each episode is highlighted by Zahn's riveting exclusive interviews, which draw out different viewpoints from the people personally connected to tragedies that rocked their local community and the investigations that attempted to piece together the truth On the Case with Paula Zahn.

Earth is visited by an alien species that threatens humanity's existence. Events unfold in real time through the eyes of five ordinary people across the globe as they struggle to make sense of the chaos unraveling around them.

This James Gunn-created series continues the saga of Peacemaker, a vainglorious superhero/supervillain who believes in peace at any cost — no matter how many people he has to kill. After a miraculous recovery from his duel with Bloodsport, Peacemaker soon discovers that his freedom comes at a price.

48 Hours is a CBS news magazine that investigates intriguing crime and justice cases that touch on all aspects of the human experience. Over its long run, the show has helped exonerate wrongly convicted people, driven the reopening -- and resolution -- of cold cases, and changed numerous lives. CBS News correspondents offer an in-depth look into each story, with the emphasis on solving the mystery at its heart. The program and its team have earned critical acclaim, including 20 Emmys and three Peabody Awards.