Restive 'Downton Abbey' fans need fret no more: PBS has confirmed that Season 2 will (finally!) premiere in the US on Sunday January 8, 2012. The AP reports Paula Kerger, PBS president, as saying that the abrupt ending to Season 1 and the paucity of episodes -- there were only four -- led to angry phone calls from fans, many of whom worried that PBS might not even air a second season.

PBS also has good news for 'Sherlock' fans. The 21st-century twist on Conan-Doyle's deerstalker-wearing detective will start its second season on PBS on Sunday May 6, 2012. Alas, it's only three episodes long, but fans can be assured that it should be a case of quality triumphing over quantity.

Other gems from the PBS spring lineup include a two-part examination of Bill Clinton's presidency, a look at some celebrity family trees by Harvard professor Henry Louis Gates, and a series on American infrastructure, 'America Revealed,' hosted by winner of 'Survivor: Cook Islands,' Yul Kwon. More on these after the jump.

The 'American Experience' documentary on Clinton will premiere on President's Day, Monday February 20, 2012. Kerger said it features fresh interviews with many who served in the Clinton administration and some of the former president's adversaries, but it doesn't include a new interview with Clinton himself.

In 'Finding Your Roots,' Gates crosses over into 'Who Do You Think You Are?' territory as he explores the historical trends around the family roots of celebrities including Kevin Bacon, Barbara Walters, Tyra Banks and Martha Stewart. The ten-part series premieres Sunday March 25, 2012.

Based on UK show 'Britain from Above,' PBS' new four-part series 'America Revealed' was originally slated to debut as part of the Fall 2011 season, but is now premiering Wednesday April 11, 2012. Using aerial footage, HD video and real-time satellite data, 'America Revealed' traces the movements and communications that miraculously come together to manufacture goods, transport people and materials.

The host, adventurous technology expert and communications attorney Yul Kwon, will show how infrastructure is changing things like traffic flow and food production. Executive producer Tony Tackaberry said: "The aerial photography, along with a range of pioneering visual techniques the series will employ, will give viewers a glimpse of the nation as they've never seen it, while the previously untapped data will offer new insight into the forces that shape our everyday lives."

Check out AOL TV's full 'Downton Abbey' coverage here.

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