Which brings to Clara's biggest moment, the reason Clara is one of the most important companions in the show's history. The Impossible Girl mystery may not have thrilled fans but its conclusion in the Series Seven finale The Name Of The Doctor certainly delivered. In a brilliant pre-title sequence Clara meets the First Doctor and Susan on Gallifrey and convinces them to pick the right TARDIS. From there she encounters every subsequent Doctor, appearing in multiple episodes from Castrovalva to Dragonfire. It was a very fun sequence that also helped to celebrate the show's 50th anniversary in an unexpected way. But the most significant moment was the choice Clara made later in that episode to save the Doctor even at the possible cost of her own life. The Great Intelligence had jumped into the Doctor's time-stream, corrupting every victory into a defeat. Without hesitation she threw herself into the fire and became not just a hero but the most significant, important companion the Doctor ever encountered. Clara Oswald 1986-2015