am_mast_grn_fire_love_canalThe best way to mark Earth Day probably is to leave the set off altogether.

But since that’s not your choice, may I suggest a concise and eye-opening history of environmental activism on “American Masters” (PBS, 9 p.m.) of all places. The series, formerly a biography showcase for cultural and arts figures is the showcase for Mark Kitchell’s succinct history “A Fierce Green Fire,” named after a book whose althor Philip Shabecoff is among the many who appear.

Broken into five acts, it stretches back to the earliest battles between John Muir and the National Parks Service over dams — the first environmental fight. As late as 1968, there was a real threat to dams closing the Grand Canyon. Maybe more shocking was the deadly effects of toxic waste at Love Canal, near Niagara, N.Y., that led to houswife activists holding EPA figures in custody until they promised to clean things up or move families. Ashley Judd narrates this segment; other celeb narrators include Robert Redford, Meryl Streep and Isabel Allende.

What happened to this rich history? The same thing that happened to environmentalism. After a slew of federal laws were signed during the Nixon administration, of all things, it was Reagan who put a stop to it all, complaining of environmental extremists. Now, of course, there’s a real struggle in convincing half the country that climate change is real, despite proof presented by  97 percent of scientists. Ecology is a global concern, so there are reports of saving the Amazon rainforest and Greenpeace’s noble struggles to save whales. At a time when premium networks are presenting their own urgent, celebrity-studded environmental documentaries that stretch out hours, sometimes it’s good to be slapped in the face, as this one does.

It’s accompanied by a new “Frontline” (PBS, 10 p.m., check local listings) that examines the effect of solitary confinement. Filmmaker Dan Edge found the solitary confinement cells a Maine maximum security prison maddeningly noisy. The prisoners there are among the estimated 80,000 currently held in solitary, a punishment now considered both inhumane and counter-productive. It’s the first of a two film series on prisons in the U.St. Next week’s looks at the sheer number of prisoners in the nation — 2.3 million.

Katie Stevens, who pretty much disappeared from TV after her stint in the “American Idol” Top 10, returns to co-star in “Faking It” (MTV, 10:30 p.m.) about high school girls who fake being lesbians because they think it will help them be popular in school. A feature I wrote on Katie’s new role can be found here.

The soon to retire host of “Late Show with David Letterman” (CBS, 11;35 p.m.) hosts his successor, Stephen Colbert, in a promising new episode.

Still time to jump in for all the delights of the new “Fargo” (FX, 10 p.m.) in which Bob Odenkirk is new chief, who puts the kibosh on investigating of Martin Freeman’s Lester. Meanwhile, new characters emerge from Oliver Platt as a grocery king and Kate Walsh as a not too grieving widow. Also popping up: Glenn Howerton of “It’s Always Sunny in Philadelphia” and Adam Goldberg as a henchman from Duluth. Set your DVR correctly: It plays until 11:15 p.m.

They came together on reality TV so it seems right that the marriage of Tori Spelling and Dean McDermott would happen on a reality series as well. The new one, her fourth overall, is called “True Tori” (Lifetime, 10 p.m.).

In the latest in the series of documentaries leading up to the world cup, “30 for 30: Soccer Stories” (ESPN, 7 p.m.) looks at “Maradona ’86’ and the problems in the 1974 World Cup with Chile, Pinochet and the Soviet Union.

Restaurants compete to make the best dish of comfort food for money on the new “Chow Masters” (Travel, 9 p.m.). The first competition is among breakfast sandwiches in New York.

A 10th season starts for “The Deadliest Catch” (Discovery, 9 p.m.). It comes with its own preshow, “The Bait” (Discovery, 8 p.m.) an hour earlier.

A winner is named in the sixth season finale of “Face Off” (Syfy, 9 p.m.) after a determining challenge in which the final three create pairs of alien characters that have to have a dance off.

They have to build larger than life characters on “Jim Henson’s Creature Shop” (Syfy, 10 p.m.).

Not to be confused with the movie or the sitcom starting later this week, the plural “Bad Teachers” (Investigation Discovery, 10 p.m.) is about the dark side of esteemed instructors.

The first season of “Chrisley Knows Best” (USA, 10 p.m.) comes to a merciful end.

The concept of beauty is considered on a new “Inside Amy Schumer” (Comedy Central, 10:30 p.m.).

No surprise that Mindy doesn’t get along with cops on a new  episode of “The Mindy Project” (Fox, 9:30 p.m.).

Two vocalists go home on “The Voice” (NBC, 8 p.m.), leaving us with an even Top 10. And Shakira sings.

Rachel makes her Broadway debut as “Funny Girl” opens on Broadway on “Glee” (Fox, 8 p.m.).

Great hospital shows from the past, from “St. Elsewhere” and “ER” to “Medical Center” are part of tonight’s episode of “Pioneers of Television” (PBS, 8 p.m., check local listings).

The week-long prime time salute to John Wayne continues on Turner Classic Movies with“Stagecoach” (8 p.m.), “The Man Who Shot Liberty Valance” (10 p.m.), “Fort Apache” (12:15 a.m.), “The Searchers” (2:30 a.m.) and “The Long Voyage Home” (4:45 a.m.).

NBA Playoff games today include Atlanta at Indiana (TNT, 7 p.m.), brooklyn at Toronto (NBA, 8 p.m.) and Washington at Chicago (TNT, 9:30 p.m.). In the Stanley Cup playoffs, Tampa Bay at Montreal (NHL, 7 p.m.), Boston at Detroit (NBC Sports Network, 7:30 p.m.), Rangers at Philadelphia (CNBC, 8 p.m.) and San Jose at Los Angeles (NBC Sports, 10 p.m.).

Baseball includes Yankees at Boston (MLB, 7 p.m.).

Daytime Talk

Kelly & Michael: Robin Roberts, Jon Jones. The View: James Franco, Chris O’Dowd, Leighton Meesner, Tamla Mann, Jawn Muray. The Talk: Ian Somerhalder, Kevin Frazier, ChiLan Lieu. Ellen De Generes: Ellen Pompeo, Philip Philip Phillips. Wendy Williams: RZA, Cirque du Soleil.

Late Talk 

David Letterman: Stephen Colbert, Robin Roberts, Kelis, Sam Moore. Jimmy Fallon: David Duchovny, John Oliver, Rita Ora. Jimmy Kimmel: Don Rickles, Emily Deschanel, Beck. Seth Meyers: Sofia Vergara, Natalie Dormer, Jonah Keri. Craig Ferguson: Cedric the Entertainer, Billie Piper. Carson Daly: Jared Harris, the Growlers, Andrew Schultz. Tavis Smiley: Joseph Stiglitz, Ian Somerhalder. Jon Stewart: Sen. Elizabeth Warren. Stephen Colbert: George Will. Arsenio Hall: Marion Wayans, Jared Harris, Gabriel Iglesias, Joe Satriani. Conan O’Brien: Zac Eron, Michael B. Jordan, Miles Teller, Ellie Kemper, Neko Case (rerun). Chelsea Handler: Wiz Khalifa, Jen Kirkman, Fortune Feimster, Bobby Lee, T.J.Miller.  (rerun).  Pete Holmes: Davi Wolfe (rerun0.