Richard John Bingham, 7th Earl of Lucan (born 18 December 1934), known as Lord Bingham from 1949 to 1964, was or is a missing British aristocrat who disappeared on 8 November 1974 after his children's nanny Sandra Rivett was found murdered. Lucan's current whereabouts are unknown, and many, including his wife, presume him to be dead.

http://en.wikipedia.org/wiki/Richard_Bingham,_7th_Earl_of_Lucan

http://en.wikipedia.org/wiki/Ambrose_Bierce

In October 1913 the septuagenarian Bierce departed Washington, D.C., for a tour of his old Civil War battlefields. By December he had proceeded on through Louisiana and Texas, crossing by way of El Paso into Mexico, which was in the throes of revolution. In Ciudad Juárez he joined Pancho Villa's army as an observer, and in that role participated in the battle of Tierra Blanca.

Bierce is known to have accompanied Villa's army as far as the city of Chihuahua. After a last letter to a close friend, sent from there December 26, 1913, he vanished without a trace, becoming one of the most famous disappearances in American literary history. Several writers have subscribed to the speculation that he actually headed north to the Grand Canyon, found a remote spot there and shot himself, though no shred of actual evidence exists to support this view. All investigations into his fate have proved fruitless, and despite an abundance of theories his end remains shrouded in mystery. The date of his death is generally cited as "1914?".

In one of his last letters, Bierce wrote the following to his niece, Lora:

"Good-bye — if you hear of my being stood up against a Mexican stone wall and shot to rags please know that I think that a pretty good way to depart this life. It beats old age, disease, or falling down the cellar stairs. To be a Gringo in Mexico — ah, that is euthanasia!"

February 1980
Brian Ingram, an 8-year-old boy, finds $5,800 in decomposing $20 bills by the edge of the Columbia River near Vancouver, Washington. The FBI matches the serial numbers on those bills to the Cooper ransom. It is the only Cooper money ever to be recovered.

via.
http://nymag.com/news/features/39617/

Harold Edward Holt, CH (5 August 1908 – 17 December 1967) was an Australian politician who became the 17th Prime Minister of Australia in 1966. His term as Prime Minister dramatically ended in December of the following year when he disappeared while swimming at Cheviot Beach near Portsea and was presumed drowned.

Holt spent 32 years in Parliament, including many years as a senior Cabinet Minister, but was Prime Minister for only 22 months. This necessarily limited his personal and political impact, especially when compared to his immediate predecessor Robert Menzies, who was PM for a total of 18 years.

The above was taken from
http://en.wikipedia.org/wiki/Harold_Holt

Those dates don't seem quite right.