A powerful tornado is a terrifying phenomenon that continues to defy decades of scientific efforts to predict it. During one of the worst tornado seasons on record, a NOVA camera team chased across the Midwest, capturing hair-raising footage of highly destructive twisters in action. But this is much more than just another “extreme weather” show, focusing on the efforts of two scientists at the University of Oklahoma to develop radically different approaches to forecasting twisters. With jaw-dropping 3-D graphics generated by the National Center for Supercomputing Applications, “Hunt for the Supertwister” features spectacular footage of terrifying twisters and gives viewers a front-row seat to the risky and thrilling art of storm chasing.

“One of the holiday’s best TV traditions.”- USA Today

On the eve of Memorial Day, join co-hosts Joe Mantegna (“Criminal Minds”) and Gary Sinise (“CSI: New York”) for a night of remembrance featuring an all-star line-up performing with the National Symphony Orchestra. The 24th annual broadcast of the NATIONAL MEMORIAL DAY CONCERT airs live from the West Lawn of the U.S. Capitol before a concert audience of hundreds of thousands, millions more at home, and to our troops around the world on the American Forces Network.

ANTIQUES ROADSHOW host Mark L. Walberg discusses Northwest Coast Indian masks with appraiser Ted Trotta at the Burke Museum of Natural History and Culture. Seattle becomes the city that sparkles with the discovery of a late-16th-century diamond and enamel jewel. Other notable finds include a moose, elk and buffalo hide chair; an 1880s Crazy Quilt; and a white Steiff clown bear worth $2,500-$3,200.

Before there was Tallahassee, there was Anhaica. This WFSU-TV documentary looks at the Big Bend area when the first European explorers arrived at Anhaica, the capital of the Apalachee people. From the culture of the Apalachee to the creation of Spanish missions, to the community we know today, it all began “Once upon Anhaica.”

More on Florida Footprints Once Upon Anhaica

By the 18th and 19th Century, Northwest Florida had been known to the Europeans for hundreds of years, but this area was far from tame. Spanish, French, British, American and Native Americans fight for control over “A Feral Land” once known as La Florida.

In the second of our ongoing documentary series, we explore the political, personal and physical battles in the area following the fall of the Spanish missions.

More on Florida Footprints A Feral Land

In this last episode, Sagal travels to Iceland, where after the country’s economic collapse, leaders decided to create a new constitution, looking to the U.S. Constitution for inspiration. This prompts Sagal to consider why our own founding document has lasted more than 225 years. He looks at the systems that have kept the Constitution healthy — amendments, judicial interpretation, checks and balances — and also at the political forces that threaten to undermine the framers’ vision: excessive partisanship leading to gridlock, money in politics and gerrymandering.

Breathing new life into the traditional civics lesson, Peter Sagal (host of NPR’s “Wait, Wait … Don’t Tell Me”) travels across the country on a Harley Davidson to find out where the U.S. Constitution lives, how it works and how it doesn’t; how it unites us as a nation and how it has nearly torn us apart. Sagal introduces some major constitutional debates today and talks with ordinary Americans and leading constitutional experts about what the Constitution actually says and what it means, the dramatic historical events and crises that have defined it, and why all this matters.

More on Constitution USA with Peter Sagal

Plantations, cotton and slavery were a big part of middle-Florida’s economy by 1860, but the election of a new President challenged that lifestyle. Florida Footprints follows the path the state took once it chose to march down “The Confederate Road.” From slavery and plantations to salt making and soldiers, we explore the skirmishes, battles, and life in Florida during the Civil War.

More on Florida Footprints The Confederate Road

At 2:50 p.m. on April 15, two bomb blasts turned the Boston Marathon finish line from a scene of triumph to tragedy, leaving three dead, hundreds injured and a city gripped by heartbreak and terror. Less than five days later, the key suspects were identified and apprehended, with one dead, the other in custody. How did investigators transform the chaos of the bombing into a coherent trail of clues, pointing to the accused killers? NOVA follows the manhunt step-by-step, examining the role modern technology — combined with old-fashioned detective work — played in cracking the case. Given hundreds of hours of surveillance and bystander videos, how did agents spot the bad guys in a sea of spectators? Why couldn’t facial recognition software I.D. the criminals? How much could bomb chemistry analysis, cell phone GPS, infrared imagery and crowd sourcing reveal about the secrets behind this horrific crime? With the help of top criminal investigators and anti-terrorism experts, NOVA explores which technological innovations worked — and which didn't — in the most notorious case of today, and how the world of crime fighting could be transformed tomorrow.

The new program, "Oklahoma's Killer Tornadoes," will update the previous NOVA episode "Deadliest Tornadoes" with new information about the May 20, 2013 tornado that swept through Moore, Oklahoma and surrounding areas, and will highlight the new radar system put in place to track tornadoes since the program originally premiered.

On May 20, 2013, a ferocious F5 tornado more than a mile wide tore through Moore, Oklahoma, causing 24 deaths and obliterating entire neighborhoods. It was the third time an exceptionally violent tornado had struck the city in 14 years. Yet predicting when and where such killer storms will hit still poses a huge challenge. Why was 2011 — the worst ever recorded tornado season that left 158 dead in Joplin, Missouri —followed by the quietest ever year of activity prior to the Moore disaster? Can improved radar and warning technology explain why fewer died in Moore than in Joplin? And will tornadoes get worse as Earth's climate heats up? In this NOVA special, meet scientists in the front ranks of the quest to understand extreme weather events. Also meet storm survivors whose lives have been upended, and learn how we can protect ourselves and our communities for the uncertain future.

The fourth historical documentary in the WFSU-TV series "Florida Footprints"
debuts Thursday, May 30th at 7:30 pm. " A State of Change" explores the Big
Bend and Panhandle area as Florida transitions through the uncertain times
of following the Civil War and into the rapidly changing world of the 20th
Century. From agriculture to education and from law enforcement to
transportation, follow the footsteps of the men and women who lived the
history of our state.

More on Florida Footprints A State of Change