Highlights 4/19 to 4/25

Nature at 7 p.m. Sunday looks at some of the most endangered species on the planet and the intensive actions being taken to keep them alive.

Masterpiece Classic at 8 p.m. Sunday presents part four of “Little Dorrit,” as Amy stays in Venice, while the rest of the Dorrits find scandal in London.

Historic Texas Courthouses at 10:30 p.m. Sunday features Texas’ county courthouses that are considered to be among the treasures of American civic architecture.

American Experience We Shall Remain at 8 p.m. Monday tells the story of two Shawnee brothers, Tenskwatawa and Tecumseh, who came closer than anyone in creating an Indian nation that could exist alongside and separate from the United States.

Appalachia: A History of Mountains and People at 9:30 Monday traces the story of the region from the beginning of the Revolutionary War through Andrew Jackson’s forced relocation of the Cherokee people in 1831.

Tom and Ray Magliozzi of NPR’s “Car Talk” examine the emerging technologies and ideas about cars, and the possibilities the future holds in transportation in Nova at 7 p.m. Tuesday.

Frontline at 8 p.m. Tuesday investigates the rising hazards contaminated water poses to human health and the eco-system and why it’s so hard to keep our waters clean.

Green Builders at 10 p.m. Tuesday profiles a cast of green building pioneers who have taken the leap into making more energy-efficient and environmentally friendly places.

Carefully analyzing weapons, slave artifacts and personal effects, Secrets of the Dead at 7 p.m. Wednesday follows marine archeologists as they discover and excavate Blackbeard’s lost pirate flagship.

Jean-Michel Cousteau and his team of explorers travel to both the northern and southern hemispheres in search of killer whales, discovering that orcas are not very different from people in Ocean Adventures at 8 p.m. Wednesday.

Musical legend Van Morrison performs songs from his latest album “Pay the Devil” and timeless classics in his first appearance on Austin City Limits at 10 p.m. Wednesday and 11 p.m. Friday.

Journalist and author Carl Hiaasen talks about his writing career on Texas Monthly Talks at 7 p.m. Thursday.

Witness the Grand opening of the Bass Concert Hall renovation with exclusive performance footage of John Legend on Docubloggers at 7:30 p.m. Thursday.

09.13.08 Hurricane Ike at 8 p.m. Thursday details the destruction of Hurricane Ike along the Texas Gulf Coast.

Live from the Artists Den at 9 p.m. Thursday features former Wallflowers member Jakob Dylan, son of music legend Bob Dylan, as he performs with his band, the Gold Mountain Rebels.

Internationally acclaimed chef Todd English journeys to Peru in search of culinary inspiration, drawing from the native cuisines and ingredients in Food Trip with Todd English at 9 p.m. Friday.

Andrea Bocelli, Josh Groban, Michael Buble and Katherine McPhee among many others, come togeth in this Great Performances at 7 p.m. Saturday in celebration of legendary songwriter and producer David Foster.

Judi Dench and Geoffrey Palmer bring their beloved television characters Jean Pargetter and Lionel Hardcastle back to life in this As Time Goes By special at 9 p.m. Saturday.