1978 - Adoption of a new constitution gives the monarchy more than a titular or ceremonial role in the government.
1981 - An attempted coup is blocked when forces loyal to the King refuse to join the rebellion.
2000 - Celebrates silver jubilee, 25th anniversary on the throne.
March 11, 2004 - Addresses the nation and visits the wounded after a terrorist attack claims 191 lives, and more than 1,800 wounded, when 10 bombs go off on four commuter trains during rush hour in Madrid.
October 2006 - Investigation begins into accusations surrounding bear hunting in Russia and shooting Mitrofan, a tame bear raised in captivity, after the bear had been fed honey spiked with vodka and released to make killing him easier.
August 2007 - Popularity with the public is falling due to royal household spending, the Russian bear incident and the questionable fitness of Prince Felipe to rule.
November 10, 2007 - Tells Venezuelan President Hugo Chavez, "Why don't you shut up?" (¿Por qué no te callas?), during the Ibero-American summit in Santiago, Chile.
February 18-19, 2009 - With Queen Sofia, visits Pensacola, Florida in honor of the city's 450th birthday. After Pensacola they travel to Miami. They do not visit Washington, DC.
May 8, 2010 - Has growth removed from right lung, which turns out to be benign.
August 8, 2010 - With Queen Sofia, hosts Michelle Obama and her youngest daughter, Sasha, at the summer palace on Mallorca Island.
April 14, 2012 - King Juan Carlos undergoes hip replacement surgery after falling during a trip to Botswana.
July 2012 - Is dropped as honorary president of the World Wildlife Fund - Spain after his April Botswana hunting trip is criticized for its extravagance during an economic crisis. He held the honorary post since 1968.