Democrats just used a famous tactic to get the Senate to vote on guns - and it has a fascinating history

Early Thursday, Sen. Chris Murphy of Connecticut pushed to bar people on the government's terrorism watch list from getting gun licenses.

Murphy, who was in office when 20 children and six staffers at Sandy Hook Elementary School were massacred by a lone gunman in 2012, also proposed expanding background checks to people buying guns at gun shows and online.

He spoke for more than 15 hours before Republicans agreed to vote on two proposed gun-control measures.

Senate Democrats launched their fight for more gun control with renewed energy this week following last weekend's shooting at a gay nightclub in Orlando, in which 49 people were killed and dozens more wounded.

The filibuster in the US Senate is a tactic used to delay or completely obstruct a measure from coming to a vote, or simply to make a political statement. The rules allow a senator to speak as long as they want, until three-fifths of senators invoke cloture, bringing the debate to a close. But the speaker must stay standing the entire time, avoid bathroom breaks, and consume only water, milk or hard candies. Some say Murphy's speech doesn't fit the true definition of a filibuster because it was designed to force a vote on a bill, not block it, but others say Democrats are using the tactic to delay voting on the appropriations bill that contains the gun control measures.

Senators are allowed to bring allies to ask questions, giving them a break from talking - though they're allowed to talk about whatever they want.

Here's a look at some of the most memorable filibusters in US history.