Regeneration Drama
Why Did David Tennant's Doctor Regenerate in Doctor Who?

Discover why David Tennant's Doctor regenerated due to radiation poisoning in a pivotal Doctor Who episode, marking the transition to Matt Smith.

Regeneration Pain
Why Did the 10th Doctor Leave Doctor Who? Explained

Discover why the 10th Doctor, played by David Tennant, left Doctor Who after saving Wilfred Mott and facing regeneration.