Sagan reflects on the future of humanity and the question of 'who speaks for Earth?' when meeting extraterrestrials. He discusses the very different meetings of the Tlingit people and explorer Jean-François de La Perouse with the destruction of the Aztecs by Spanish conquistadors, the looming threat of nuclear warfare, and the threats shown by destruction of the Library of Alexandria and the murder of Hypatia. The episode ends with an overview of the beginning of the universe, the evolution of life, and the accomplishments of humanity and makes a plea to mankind to cherish life and continue its journey in the cosmos. The Cosmos Update notes the preliminary reconnaissance of planets with spacecraft, the fall of the Berlin Wall and the end of apartheid in South Africa, and measures towards the reduction of nuclear weapons.

Salvador Dali's strange crucifixion is often called the greatest religious painting of the 20th century. Yet its artist was a notorious blasphemer some of whose work had outraged the Catholic Church. The Christ of St John of the Cross by Salvador Dali is the first of two extraordinary crucifixions painted by Dali in the early 1950s. The painting is based on a 'cosmic dream' Dali is said to have had, in which the nucleus of the atom was a figure of Christ himself.
The painting offers a surrealist view of the crucifixion of Christ, and is based on a drawing by the 16th century Spanish friar Saint John of the Cross. But Dali's vision was somewhat unique, using an unusual artistic perspective in which Christ is seen from above. His Christ of St. John of The Cross was inspired by a weird mix of Spanish mysticism and nuclear physics, with his Christ being modelled by a Hollywood stuntman. It's also a masterpiece of painting technique.