For 45 centuries, the Great Sphinx has cast its enigmatic gaze over Egypt's Giza plateau. The biggest and oldest statue in a land of colossal ancient monuments, its scale is staggering: the mighty head towers as tall as the White House, while its body is nearly the length of a football field. This strange half-human, half-lion image has inspired countless fantastic theories about its origins. How was it built, and who or what does it represent? Surprisingly, the scribes of the period when it was built — during Egypt's Old Kingdom — passed over it in silence. Adding to the mystery, archeologists found that its creators abruptly discarded their tools and abandoned the structure when it was nearly complete.

As snow falls and Christmas lights glow in Jackson Hole, a holiday season of a different sort settles in just beyond the town, in the great winter world of Yellowstone. Breathtaking landscapes frame intimate scenes of wolves and coyotes, elk and bison, bears and otters as they make their way through their most challenging season of the year. NATURE journeys in the footsteps of the men who first explored the park, and travels with their modern-day counterpart on his own journey of discovery. From the unique crystals of individual snowflakes to the grand sweep of Yellowstone's Hayden Valley, this is a Christmas like no other.

Filmed around the United States – from Los Angeles to Washington, DC – this documentary chronicles the underreported history of a group of immigrants finding refuge, overcoming adversity and ultimately creating new lives in the United States. Even though Iran is in the news virtually every day, many Americans have little knowledge of the story of the hundreds of thousands of Iranians who live in the U.S.

Hear the story of how the Founding Fathers raised the ideal of religious freedom to the level of a fundamental human right — told through re-enactments, the Founding Fathers’ own words and the commentary of key experts. The documentary profiles the lives and times of the colonial Americans — including Jefferson, Franklin and Washington — who codified freedom of conscience for the first time in human history as an inalienable right protected by law.

This week on MARKET WARRIORS, pickers Miller, John, Bob and Kevin head out to Canton, Texas, home to First Monday Trade Days — a large outdoor monthly market with a mixture of antiques and new wares. The challenge to find authentic Mission Oak furniture amid the recently made crafts puts one picker up against the clock. Off-screen host Mark L. Walberg injects quick wit and a collector’s know-how as the pickers scour the market for key finds, which include a pair of Knoll Chairs, a Bostrom Brady Surveying Tool and an antique document box. The winning picker is determined at A.N. Abell Auction Company in Los Angeles, California, where chosen items go under the hammer.

A Louis Comfort Tiffany necklace from a husband or a Fender bass guitar as a birthday present — these memorable gifts turned out to be valuable and interesting items. “Greatest Gifts,” filled with appraisals featuring items that guests received as presents, will have you writing your own holiday wish list.

As the war nears its end, Downton’s aristocrats and servants put their lives back together. Mary and Sir Richard go estate hunting. A mysterious wounded officer makes a shocking revelation.

In the climactic battle of the war, Matthew and William go over the top to an uncertain fate. Vera plays a cruel endgame with Bates and Anna. And Daisy faces the severest test of her life.

The a cappella phenomenon Straight No Chaser -- the ten men whose quirky version of “The 12 Days of Christmas” is a YouTube sensation -- bring holiday cheer to PBS, singing holiday favorites with a twist, like “The Christmas Can Can” and “Hey Santa!” and, of course, the song that started it all, “The 12 Days of Christmas”!

Emmy and Golden Globe-winning actress Jane Seymour and Grammy Award-winning baritone Nathan Gunn join the renowned Mormon Tabernacle Choir and Orchestra at Temple Square in a magnificent Christmas special featuring some of the season’s best-loved songs.