Oil prices fall after Donald Trump retreats on Iran strikes. Also, Trump sends ICE to airports amid the TSA funding fight. And the North Carolina race is key to Democrats taking the U.S. Senate. Rep. Adam Smith, Amos Hochstein, Rep. James Walkinshaw, and former Gov. Roy Cooper join Lawrence O'Donnell.

Whether it's a cost-cutting move to save on some of the Titanic's three million rivets, or a shortcut taken while building a gladiator stadium in ancient Rome, it takes just a little carelessness to trigger the deadliest engineering failures in history.

Trump's eventful weekend of golfing, sightseeing, and ignoring the imploding effects of the war in Iran has Jon Stewart wondering who the hell the president has been claiming to negotiate with overseas, and whether this "top person" even exists. Plus, airport chaos amid a government shutdown has ICE filling in for the TSA as part of Trump's escalating chaos rampage.

Jake Sullivan, former National Security Advisor, Harvard Kennedy School professor, and co-host of "The Long Game" podcast, joins Jon Stewart to break down the war in Iran, U.S. foreign policy, and the future of nuclear negotiations. Sullivan shares his insights on President Trump's approach to Iran and Iran's "coherent and clear" strategy. Plus, Sullivan reflects on his time working on secret negotiations with Iranian officials during the Obama administration and tells the story of a historic first direct contact between U.S. and Iranian presidents since 1979.

Woo-seok spots links between the artwork fire incident and his sister's accident. Seol-ah follows Jun-beom to his villa, and the truth is revealed.

Scenic northern Yatsugatake in Nagano Prefecture is an outdoor lover's paradise just two hours from Tokyo. It's defined by a series of peaks rising above 2,000 meters. Novice mountaineers can enjoy snow climbing safely if they travel with a guide and proper equipment.
This time Michael Keida, who is new to mountaineering, traverses the area on cross-country skis, snowshoes and with crampons to fully explore the snowy mountains.

Guests include Taraji P. Henson & Cedric the Entertainer, Flea, Camila Morrone and musical guest Flea.

1. James Marsden ("Mike & Nick & Nick & Alice" and "Your Friends & Neighbors"). 

2. D'Arcy Carden ("Sunny Nights"). 

3. Musical Guest Jeff Tweedy.

Guests include Sterling K. Brown (Paradise) and Rachel Dratch (The Rocky Horror Show). 

Bea's emotions get the better of her, Zoe is blindsided , and the Panesars and the Brannings attempt to bond.

A passenger flies in with soup sachets which leave a bitter taste, a family fails to declare their airsoft arsenal and alarms bells are ringing after an interview with sisters.

Two commuters brake-check and abuse each other. A whiskey induced wipeout on the bridge. Flying carpets and flipping cars.

Theo tries a charm offensive on George and Christina, Kit panics when Mal names his attacker, Betsy and Dylan babysit Connie, and Hope warns Sam against listening to Daniel.

Cain explodes with suppressed rage, Tracy is guilty, and Dawn questions Kim.

Warren decides who he wants, but he may be too late, and friends gather around to support Diane and Tony.

An attempt to decipher a constellation from the Dark World suggests that it is related to the ancient vampire rune "Cain". Seryoga is trying to find a way to send his mother home.

Natasha and Seryoga are sent to catch a werewolf fox that is terrorizing couriers. Lyokha, Nikitich, and Apollon go to Arkaim and find a tomb with three sarcophagi.

Tensions peak as shifting alliances, bold moves and rising rivalries reshape the tribe. Power balances wobble and players scramble to outmanoeuvre each other in a fast changing game.

Homestay Week continues as our couples get a taste of life outside the experiment. But as they see what their partners natural environment looks like, tough questions will arise.

The third son of Cain is being held captive at the border. The King of the Dark World is coming to collect his subject in person.

Foreign Correspondent this week heads to Greece for a rather concerning problem...

Greece is one of the world's most popular tourist destinations – more than 30 million visitors travel there every year. But extraordinarily, Greece itself is in danger of running out of Greeks. The population is in freefall with predictions it will drop by twenty percent by 2050.

On Foreign Correspondent reporter Rhiannon Shine travels to the birthplace of her grandparents to see the problem first hand. Right across the country, ghost towns are becoming all too common. There are far more deaths than births, young people have left in droves and migration is deeply unpopular. If modern Greece can't solve its population problem, it's at risk of joining its ancient ancestors as a living museum.

TODAY's Consumer: Beauty Products and Recycling, Where Do They Go? TODAY's Consumer: How to Shop Reviews Smartly with Sarah Eggenberger. Celebrating Baseball In America: Little League Players Spring Training on the Plaza.

Catherine Fisher, LinkedIn career expert.

"American Idol" judges Lionel Richie, Luke Bryan and Carrie Underwood; actor Andrew McCarthy discusses his new book ("Who Needs Friends: An Unscientific Examination of Male Friendship Across America"); 20th anniversary of "Hannah Montana" with ABC News contributor Kelley L. Carter; Deals & Steals with ABC e-commerce editor Tory Johnson.

Daredevil is in hiding, but he isn't laying low. A shadowy player from Washington, D.C. emerges.

⁨⁨Torbjørn and Agnes face Peter and Vår, in a match that both should preferably win to keep their playoff dream alive.

The weeds are to be controlled without the use of pesticides. New tenants move in, and Ellen is irritated by an unusable chicken coop.

The team investigates a targeted explosion that wiped out a bomb squad with ties close to home.