Season Finale Time For CSI: Vegas, Alter Ego, and Tough As Nails

As the calendar year winds down, so too does the fall TV season, with three network series — CSI Vegas and Tough as Nails on CBS, and Alter Ego on FOX — set to see their season (and possibly series) finales tonight. Also today: Will Smith fronts Welcome to Earth, a National Geographic-produced nature docuseries on Disney+, The Masked Singer sets its lineup for next week's finale, and the gang buys a roller rink in a ‘90s-set episode of It’s Always Sunny in Philadelphia. Here’s what’s new and noteworthy on TV this Wednesday:

CSI: Vegas: Season finale. When David Hodges (Wallace Langham) goes missing, the entire CSI team searches for evidence that can help locate him, clear his name, and save the reputation of the crime lab. While billed as a limited series, ratings have been strong enough for CS!: Vegas that we wouldn't be surprised to see it return for another season. Watch preview. 10:00 PM ET on CBS

Tough as Nails: Season finale. The final four contestants compete in one last challenge in hopes of winning the $200,000 grand prize and a Ford Super Duty truck. 9:00 PM ET on CBS

Alter Ego: Season finale. The final four transform into their dream avatars one last time for a chance to be named champion. 9:00 PM ET on FOX

Welcome to Earth: Complete first season. Will Smith and National Geographic get up close and personal with volcanoes, spectacular deserts, and breathtaking swarms of animals in this six-episode nature series. Watch trailer. Streaming on Disney+

Chicago Med: Fall finale. The outcome of Will’s (Nick Gehlfuss) investigation weighs heavily on his mind as he works with Dylan (Guy Lockard) to save a 4-month-old patient. Followed by the fall finales of Chicago Fire and PD; all three shows return in early 2022. 8:00 PM ET on NBC

The Masked Singer: The final two singers from Group B perform solo, and then with celebrity duet partners and panelists Nicole Scherzinger and Robin Thicke. One will be unmasked and sent home, while the other will advance to next week’s grand finale. 8:00 PM ET on FOX

Survivor: Suddenly finding themselves in the minority alliance, DeShawn and Danny embark upon a desperate idol hunt in the penultimate episode of the season. Watch preview. 8:00 PM ET on CBS

It’s Always Sunny in Philadelphia: Back-to-back episodes find the Gang purchasing a roller rink in a ‘90s-set flashback, and replacing Dee with a monkey when they suspect she’s menopausal. 10:00 PM ET on FXX

Dr. Pimple Popper: A Pimple Carol: Holiday special. As Dr. Sandra Lee works to address patients’ skin issues before the holidays, the Spirits of Pimples Past, Present, and Future stop by to remind her of the true meaning of Christmas — and help with a few new cases. 10:00 PM ET on TLC

Christmas Around the World: Holiday special. Dean Cain and Laura McKenzie host this two-hour special about unique Christmas experiences around the world, from indoor skiing in Dubai to a month-long holiday celebration in Mexico. Featuring performances from Brandon Rogers, Olympic ice dancing champion Tatiana Navka, Garrett Clayton, and the Luys (Light) Vocal Quartet. 8:00 PM ET on The CW

Caroline Kebekus: The Last Christmas Special: Comedy special. German comic Caroline Kebekus unpacks the many headaches of the holiday season, from intense hangovers to the agony of Advent calendars. In German with English subtitles. Streaming on Netflix

CLASSIC HOLIDAY MOVIES AND SPECIALS

Dr. Seuss’ How the Grinch Stole Christmas: Jim Carrey plays the misanthropic Grinch, a solitary creature who tries to ruin Christmas by stealing gifts from nearby Whoville, in Ron Howard's 2000 adaptation of Dr. Seuss' beloved book of the same name. Watch trailer. 5:00 PM ET on Freeform

Dr. Seuss’ The Grinch: Benedict Cumberbatch lends his voice to the great green sourpuss in Illumination Entertainment's 2018 computer-animated retelling of Dr Seuss' classic Christmas story. Watch trailer. 7:30 PM ET on Freeform

National Lampoon's Christmas Vacation: Clark Griswold (Chevy Chase) decides to play it safe and celebrate the holidays at home, only to have Cousin Eddie (Randy Quaid), an out of control dog, and a series of inevitable mishaps threaten to blow up his holiday cheer faster than a match tossed in a backed-up sewer line. 8:00 and 10:15 PM ET on AMC

The Nightmare Before Christmas: When Jack Skellington, the King of "Halloween Town," stumbles upon "Christmas Town," he becomes obsessed with celebrating the holiday, and chaos soon follows. Watch trailer. 9:30 PM ET on Freeform

Visit our Holiday Viewing Guide for a complete listing of where to watch classic holiday specials and movies throughout the month of December.

Claire Spellberg Lustig is the Senior Editor at Primetimer and a scholar of The View. Follow her on Twitter at @c_spellberg.