Need to know everything about the Sontarans? The BBC Doctor Who Blog has you covered:
Strax the Sontaran returns in The Crimson Horror and in his honour we’ve maximised coverage of all his race’s early encounters with the Doctor. That means you can enjoy a wealth of clips, galleries, fact files and more from stories including the Sontarans’ debut adventure back in 1973, their attempted invasion of Gallifrey and The Two Doctors.
Clips include the very first time we saw one of their faces, the Doctor defeating an entire invasion force with a risky bluff and the Time Lord gambling to save his home planet from a ruthless Sontaran plot. They also have galleries from every single episode, fascinating behind the scene shots and exclusive content from the making of.