How long is 15,800,000 seconds?
It's about one-and-three-fifths times as long as The First artificial heart patient's survival
The length of The First artificial heart patient's survival is about 9,680,000 seconds.
(1982) (Dr. Barney Bailey Clark; first permanent, pneumatic device)
It's about one-and-two-thirds times as long as The Spanish-American War
The length of The Spanish-American War is about 9,420,000 seconds.
(1898)
It's about two times as long as The First spaceflight (Sputnik)
The length of The First spaceflight (Sputnik) is about 7,900,000 seconds.
(a.k.a. Sputnik 1, a.k.a. Спутник-1, a.k.a. "Satellite-1", a.k.a. Простейший Спутник-1) (1957) (total time in orbit)
It's about three times as long as The Voyage of the Mayflower
The length of The Voyage of the Mayflower is about 5,700,000 seconds.
(1620)
It's about three times as long as Columbus' voyage to America
The length of Columbus' voyage to America is about 6,000,000 seconds.
(1492) (first voyage)
It's about three-and-a-half times as long as The First US Continental Congress

The length of The First US Continental Congress is about 4,400,000 seconds.
(1774) (Philadelphia, Pennsylvania)
It's about six times as long as a William Henry Harrison's Presidency
The length of a William Henry Harrison's Presidency is about 2,723,000 seconds.
(a.k.a. William Henry Harrison, a.k.a. "Tippecanoe," a.k.a. "Old Tippecanoe") (1841)
It's about one-fifth as long as The Korean War
The length of The Korean War is about 97,460,000 seconds.
(1951-53) (to armistice signing)
It's about one-tenth as long as The US Civil War

The length of The US Civil War is about 126,000,000 seconds.
(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)
It's about one-tenth as long as The First walk around the world
The length of The First walk around the world is about 135,500,000 seconds.
(1970 - 1974) (Dave, John, and Peter Kunst) (including time in recovery)
It's about one-tenth as long as World War I
The length of World War I is about 138,000,000 seconds.
(a.k.a. First World War, a.k.a. Great War, a.k.a. World War, a.k.a. War to End All Wars, a.k.a. WWI, a.k.a. WW1) (1914 - 1918)
It's about one-tenth as long as World War II
The length of World War II is about 189,500,000 seconds.
(a.k.a. Second World War, a.k.a. WWII, a.k.a. WW2) (1939 - 1945)
It's about twelve times as long as Boniface VI's reign
The length of Boniface VI's reign is about 1,300,000 seconds.
(AD 896)
It's about one-fifteenth as long as The Construction of the Chunnel
The length of The Construction of the Chunnel is about 201,600,000 seconds.
(a.k.a. Channel Tunnel, a.k.a. Le tunnel sous la Manche) (1987 thru 1994) (Folkstone, Kent, UK to Coquelles, Pas-de-Calais, France)
It's about one-fifteenth as long as The American Revolutionary War

The length of The American Revolutionary War is about 264,400,000 seconds.
(a.k.a. American War of Independence) (1775-83)