i) births and deaths

16 September 2014: death of Michael Hayes, who directed Fourth Doctor stories The Androids of Tara (1978), The Armageddon Factor (1979) and City of Death (also 1979).

16 September 2016: death of Andrew Staines, who played Benik's sergeant in The Enemy of the World (Second Doctor, 1968), Goodge in Terror of the Autons (Third Doctor, 1971), the Captain in Carnival of Monsters (Third Doctor, 1973) and Keaver in Planet of the Spiders (1974). He was a nephew of Barry Letts, the show's producer for the Pertwee years.
ii) broadcast anniversaries

16 September 1967: broadcast of episode 3 of Tomb of the Cybermen. The Cybermen reveal their plan to convert all the explorers into Cybermen; the expedition have different views on this prospect.
16 September 1978: broadcast of episode 3 of The Ribos Operation. K9 rescues the Doctor and Romana from the Graff, but they encounter him again in the catacombs (with Binro the Heretic).

iii) date specified in canon

16 September 1909: Martha and the Tenth Doctor get caught up in Lord Haleston's hunt for monsters near the Lake District village of Templewell (in Stephen Cole's 2007 novel, Sting of the Zygons).