PBS is expanding its drama footprint.

The network is adding 20 new hours of anthology series Masterpiece through 2015, including Grantchester, Poldark, Indian Summers and Damian Lewis starrer Wolf Hall. The new series will join current dramas Mr Selfridge and Call the Midwife, which are returning for new seasons.

PBS has also announced premiere dates for their new titles. First Peoples, a five-part series that presents the latest genetic research exploring how humans migrated from continent to continent, will premiere Wednesday, April 29. Filmmaker Rory Kennedy's Last Days in Vietnam will bow on Tuesday, April 28, timed to the 40th anniversary of the Fall of Saigon, and will be complemented by other special programs, including The Draft, The Day the Sixties Died and Dick Cavett’s Vietnam.

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Another new series, Earth: A New Wild, hosted by leading conservation scientist Dr. M. Sanjayan, will air Wednesday, Feb. 4, as part of the network’s “Think Wednesday” science and nature night. The three-part film, Cancer: The Emperor of All Maladies, executive produced by Ken Burns and directed and produced by Barak Goodman, will bow on Monday, March 30. The next day, three-part miniseries Miracle Baby Unit, which examines the groundbreaking scientific frontier of fetal medicine, premieres.

"Our diverse schedule includes everything from award-wining documentaries to fascinating science shows to ovation-worthy arts performances. More than ever before, I can say that this winter/spring season, there’s something exceptional on PBS every night of the week," said Beth Hoppe, PBS’ chief programming executive and general manager of general audience programming.

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Hoppe adds: "What’s more, the expansion of Sunday night drama gives our audience more of what they are looking for — thrilling, gorgeous, quality storytelling. PBS offers the very best content on television and across digital platforms."

The network is strategically placing like-minded shows on the same night, a programming decision that had led to a significant increase in viewership near the end of the 2013-14 broadcast season with the fifth-largest primetime household rating among all broadcast and cable networks.