Beloved "Star Trek" star Leonard Nimoy died Friday at his Los Angeles home from chronic obstructive pulmonary disease caused by smoking. Nimoy was well-known for playing the role of Mr. Spock, a Vulcan alien, aboard the starship Enterprise in the long-running cult-fave series. He was part of the original cast in the mid 1960s. He was survived by his wife, Susan Nimoy. Below are some of the best Star Trek episodes featuring Spock.

The Menagerie

Spock abducts his former commander and sets the Enterprise on a course to a forbidden planet. The two-part episode used footage from the original pilot, titled “The Cage.”

The Galileo Seven

Spock’s leadership skills come into play when the Galileo spacecraft crash-lands on a hostile planet. The episode shows how Spock’s strictly logical style clashes with the fear and resentment of his crew, and how he has to manage that conflict.

Amok Time

This is considered by some fans as one of the essential episodes for understanding the Captain Kirk-Mr. Spock relationship. Kirk violates orders so that he can take Spock home to Vulcan, where he is to marry, but the comrades  end up in a landmark fight.

The Enterprise Incident

This is one of the episodes that was told from Spock’s point of view. Kirk is acting irrational and orders his ship into enemy space where they are captured by the enemy.

Spock's Brain

Spock’s brain is stolen by an alien force and Kirk and the ship’s physician Leonard McCoy race to retrieve it.

Shore Leave

What was supposed to be a shore leave for the Enterprise turns out to be a nightmare as the crew's imaginations turn into reality.

The Immunity Syndrome

The Enterprise encounters an enormous single-celled organism that feeds on energy and threatens the galaxy as it prepares to reproduce. The episode shows Spock's view on sacrifice and duty to the ship.