It's about three times as long as The First walk around the world
In other words, 12 years is 2.7950 times the length of The First walk around the world, and the length of The First walk around the world is 0.35780 times that amount.(1970 - 1974) (Dave, John, and Peter Kunst) (including time in recovery)
On June 20th, 1970, Dave Kunst set out from Waseca, Minnesota with $1,000 and a mule. Kunst completed his walk around the world (with a 0.33310 years pause following an assault he suffered during the journey) on October 5th, 1974 — 4.2930 years.
It's about three times as long as The Civil War (American)
In other words, 12 years is 3.01 times the length of The Civil War (American), and the length of The Civil War (American) is 0.3320 times that amount.(a.k.a. War Between the States, a.k.a. the Great Rebellion, a.k.a. the War of the Rebellion) (1861-65) (United States)
The deadliest war in American history, the American Civil War is generally considered to have begun on with the attack on Fort Sumter on April 12th, 1861 and to have lasted until the surrender of Robert E. Lee's army on April 9th, 1865 — 3.990 years. A total of 620,000 American (including Confederate) soldiers are estimated to have lost their lives due to the war.
It's about four times as long as The Korean War
In other words, 12 years is 3.8860 times the length of The Korean War, and the length of The Korean War is 0.25730 times that amount.(1951-53) (to armistice signing)
The Korean War between North Korea (a.k.a. Democratic People's Republic of Korea, a.k.a. DPRK) and South Korea (a.k.a. Republic of Korea, a.k.a. ROK) began on June 25th, 1950 during the Cold War. The war paused with the signing of an armistice on July 27th, 1953 — 3.088 years — although the war is officially ongoing and marked by occasional border conflicts.
It's about one-tenth as long as Pepi II's reign
In other words, the length of Pepi II's reign is 10 times 12 years.(a.k.a. Neferkare) (2278 BCE - 2184 BCE)
The sixth dynasty pharaoh of Egypt's Old Kingdom, Pepi II Neferkare ascended to the throne at the age of six and is generally thought to have reigned until his death at the age of one-hundred — a total of 94 years. His reign was the longest of any monarch in history.
It's about one-twentieth as long as a Giant Tortoise's Lifespan
In other words, the length of a Giant Tortoise's Lifespan is 21 times 12 years.(for Adwaita, an Aldabra Giant Tortoise) (Dipsochelys dussumieri, formerly Geochelone gigantea)
Adwaita, an Aldabra Giant Tortoise who lived the later part of his life in the Alipore Zoological Gardens in Kolkata, India, was 250 years old at the time of his death. Once a pet of Major-General Robert Clive, 1st Baron Clive, who is credited with securing India as a colony of Great Britain, Adwaita lived through the entirety of India's 190 years as a British colony.
It's about forty times as long as The First artificial heart patient's survival
In other words, 12 years is 39.10 times the length of The First artificial heart patient's survival, and the length of The First artificial heart patient's survival is 0.0256 times that amount.(1982) (Dr. Barney Bailey Clark; first permanent, pneumatic device)
On December 2nd, 1982 Dr. William DeVries implanted the first artificial heart into Dr. Barney Bailey Clark, who went on to live for 0.3070 years. This early model of the artificial heart was controlled and powered by an external, 146.51 kg (323 lb) machine that Dr. Clark had to cart with him as he moved throughout the hospital.
It's about 40 times as long as The Spanish-American War
In other words, 12 years is 40.20 times the length of The Spanish-American War, and the length of The Spanish-American War is 0.0249 times that amount.(1898)
The War between Spain and the United States over the liberation of Cuba began on April 25th, 1898 and lasted until the signing of the Treaty of Paris on August 12th, 1898, 0.2960 years. The Treaty gave the United States control of Cuba, the Philippines, Puerto Rico, and Guam.