March 7 is the 66th day of the year (67th in leap years) in the Gregorian calendar. There are 299 days remaining until the end of the year.

• 1850 – Senator Daniel Webster gives his "Seventh of March" speech endorsing the Compromise of 1850 in order to prevent a possible civil war.

• 
  1876 – Alexander Graham Bell is granted a patent for an invention he calls thetelephone.

• 1986 – Challenger Disaster: Divers from the USS Preserver locate the crew cabin of Challenger on the ocean floor.

• 1989 – Iran and the United Kingdom break diplomatic relations after a row overSalman Rushdie and his controversial novel.

• 2007 – The British House of Commons votes to make the upper chamber, theHouse of Lords, 100% elected.

• 2009 – The Kepler space observatory, designed to discover Earth-like planetsorbiting other stars, is launched.