1873

May

 * According to his diary, Professor Cornelius Perkins and his expedition discovered "a frog the size of a rhinoceros" with the leg of one of the natives in its mouth while searching for the city of the Maygor tribe, the legendary Lost City of Gold, in the Valley of Death in the Amazon. From the evidence presented in his diary, UNIT HQ came to believe that Perkins had discovered a crashed alien spacecraft in the Valley of Death. To that end, in 1977, they had the Fourth Doctor, who was still officially UNIT's scientific adviser, and his companion Leela join Edward Perkins' expedition to the Amazon to learn the fate of his great-grandfather as observers. Once they had arrived in the Valley of Death, the Doctor determined that time moved at considerably slower rate than elsewhere on Earth and throughout the universe as it existed within a time bubble. Although 104 years had passed in the outside world, only a month had gone by from Professor Perkins' perspective since he discovered the alien spacecraft. (AUDIO: The Valley of Death)

September

 * 11 - The Eighth Doctor and Mary Shelley arrived in Vienna and encountered two Cybermen. (AUDIO: The Silver Turk)

Unknown dates

 * The Seventh Doctor, Ace and Bernice Summerfield arrived in a virtual England created by Galah. (PROSE: Strange England)
 * Professor George Litefoot's family departed China after his father had died. As a going-away present, Emperor Tongzhi gave him a puzzle box which turned out to be a 51st century time cabinet. (TV: The Talons of Weng-Chiang)
 * By this time, Mondas was located 200 light-years from Earth. (AUDIO: The Silver Turk)