On April 18, 2014, an avalanche on Everest killed 16 people, more than the 1996 disaster on which this movie is based. Most of the dead were Sherpas preparing for the upcoming climbing season. Filming had to be postponed.

When Rob Hall's team is asked why they are climbing Everest, everybody answers "because it's there," a motto of mountain climbers worldwide. In a 1924 interview, George Mallory, asked why he would risk his life to become the first person to summit Everest, famously answered "because it's there." Mallory disappeared during a summit attempt in June 1924. His body was found in May 1999, 245 meters from the summit.

Vijay Lama, the helicopter pilot, is one of the most experienced pilots in Nepal.

Mount Everest was named by Andrew Waugh, British Surveyor General, in 1865. Sir George Everest, its namesake, identified it in the 1820s as the highest point in the world above sea level. The original Tibetan name, Chomolungma, means "Goddess Mother of the World". It's 29,029 feet (8,848 meters) high.

Into Thin Air author Jon Krakauer came out against the film, particularly a scene in which his character refuses to help Anatoli Boukreev's team with search and rescue. Krakauer told the Los Angeles Times, "I never had that conversation. Anatoli came to several tents, and not even Sherpas could go out ... no one came to my tent and asked." Director Baltasar Kormákur defended the film in a response, stating the scene "was to illustrate how helpless people were and why they might not have been able to go out and rescue people."

The film was released in 2015, the second year since 1974 that nobody successfully reached the summit. In 2014, the Sherpas refused to climb due to the disaster that killed 16 Sherpas.

Christian Bale was attached to play Rob Hall, but left to appear in Egzodas. Dievai ir karaliai (2014) instead. Subsequently, director Baltasar Kormákur decided to transform the film to an ensemble version of the story.

In real life, Beck Weathers' nose was so badly injured by frostbite that it had to be surgically reconstructed.

Tenzing-Hillary Airport appears briefly, as Lukla Airport. Many consider it the world's most dangerous airport due to its steeply inclined runways and treacherous surrounding terrain.

Guy Cotter, a consultant on the film, now runs Adventure Consultants, Rob Hall's old job.

This story and some stylized scenes were borrowed from the IMAX film Everest (1998).

Jason Clarke replaced Christian Bale in both this film and Terminatorius: Genisys (2015).

Survivor Lou Kasischke, a consultant on the movie, published his account of the Everest tragedy in his book, "After the Wind."

Everest is referred to as part of a group called "the 8,000", 14 mountains which rise at least 8,000 meters above sea level: Everest (Nepal: 8,848 m/29,029 ft), K2 (between Pakistan and China, 8,611 m/28,251 ft), Kangchenjunga (Nepal, 8,586 m/28,169 ft), Lhotse (Nepal, 8,516 m/27,940 ft), Makalu (Nepal, 8,485 m/27,838 ft), Cho Oyu (Nepal, 8,201 m/26,906 ft), Dhaulagiri I (Nepal, 8,167 m/26,795 ft), Manaslu (Nepal, 8,163 m/26,781 ft), Nanga Parbat (Pakistan, 8,126 m/26,660 ft), Annapurna I (Nepal, 8,091 m/26,545 ft), Gasherbrum I (Pakistan, 8,080 m/26,444 ft), Broad Peak (Pakistan, 8,051 m/26,414 ft), Gasherbrum II (Pakistan, 8,035 m/26,362 ft), and Shishapangma (Nepal, 8,027 m/26,335 ft).

Pemba Sherpa was part of the Adventure Consultants Guided Expedition as a Base Camp Sherpa. Rob Hall led this expedition.

In one scene, the team crosses Larja Dhoban, the suspension bridge above the Dudh Koshi river just before the steep climb up to Namche. Larja Dhoban is the sixth of seven suspension bridges for hikers and climbers to cross from the starting point in Lukla (where the Tenzing-Hillary Airport is located) to the Everest Base Camp.

The film cast includes five Oscar nominees: Jake Gyllenhaal, John Hawkes, Keira Knightley, Emily Watson, and Josh Brolin.

Keira Knightley shot all her scenes in six days.

Baltasar Kormákurs 13-year-old son played Beck's son, Bub.

On June 4, 2015, the first trailer for the film was released online, with an appeal for relief for the April 2015 Nepal earthquake through Oxfam America in the coda.

The film takes place from March to May 1996.

John Krakauer wrote "Into The Wild"

Robin Wright and Michael Kelly are co-stars in the Netflix series Kortu namelis (2013).

Jason Clarke and Sam Worthington have both starred in a Terminator film. Sam Worthington starred in Terminatorius: išsigelbejimas (2009) and Jason Clarke starred in Terminatorius: Genisys (2015).

The Indian song "Ladki Haye Allah" played during the opening bus sequence is from the 2001 Bollywood movie "Kabhie Khushi Kabhie Ghum" while the movie is set In 1996.

This is Walden Media's first film to be rated PG-13 by the MPAA.

Walden Media's first film with Universal Pictures. It's also the company's second film to receive a PG-13 rating by the Motion Picture Association of America.

The fourth movie starring Keira Knightley, with a soundtrack composed by Dario Marianelli. Previous movies were Puikybe ir prietarai (2005), Atpirkimas (2007) and Anna Karenina (2012).

On January 30, 2014, Universal set a release date of February 27, 2015. On March 21, it was moved to September 18, 2015.

At the start of the movie, Josh Brolin' s character (Beck Weathers from Texas) is wearing a "Kemp/ Dole 1996" t-shirt. Josh Brolin would go in to play George W Bush....another famous Texan.

Jason Clarke and Elizabeth Debicki previously starred together in Didysis Getsbis (2013).

John Hawkes and Josh Brolin also appear in Amerikos gangsteris (2007).

When Beck Weathers is invited into the tent to dance, the song playing includes the lyrics "Everywhere you go always take the weather with you". This foreshadows Rob leaving Beck when his eyes go bad.

Martin Henderson starred in Bride and Prejudice (2004) and Keira Knightley starred in Pride and Prejudice (2005).

The bodies of Andy 'Harold' Harris and Doug Hansen have never been recovered. Another expedition found Rob Hall's body almost two weeks after his death; his widow, Jan, requested that it remain there, as his last wish was most likely to stay on the mountain. As depicted in the movie, Anatoli Boukreev found Scott Fischer's body and moved it away from the climbing trail; it also remains on the mountain. Boukreev found Yasuko Namba's body almost a year later. He built a primitive tomb from stones to protect it from scavengers. When her widower found out, he financed an expedition that recovered her body later that year.

Rob Hall was the first non-Sherpa to climb Everest 5 times. His widow Jan became the second New Zealand woman to summit Everest; Lydia Bradey was first.

Anatoli Boukreev, a guide on the Mountain Madness expedition, died December 25, 1997, while ascending the Nepalese mountain Annapurna. Boukreev's memoirs, "Above the Clouds: The Diaries of a High-Altitude Mountaineer," were published posthumously in 2001.

An IMAX film crew was present on Everest during the 1996 disaster, shooting a documentary. Production halted when disaster struck, and members of the crew joined the search and rescue operation that saved Beck Weathers. They located Rob Hall's body on May 23, 1996.

The rescue of Beck Weathers was the highest flight ever achieved by a helicopter pilot. No one believed it could be done. What the film doesn't show is that Weathers, who was seriously ill, gave up his place to another climber who was in even worse condition. Weathers had no idea if the helicopter could return for him, and knew he would die if it couldn't come back. When asked about that decision, he said that it seemed like the right thing to do.

In his book "Into Thin Air", Jon Krakauer argues that some lives could have been saved if Anatoli Boukreev had used bottled oxygen in his job as a guide. Boukreev believed that bottled oxygen was not necessary if a climber was strong enough. Krakauer's accusations against Boukreev for leaving his clients on the mountain soon turned to a public dispute between their lawyers that was never settled. In 1997 Boukreev published his own book, "The Climb: Tragic Ambitions on Everest," which was partly a rebuttal of Krakauer's accusations.

The film completely omits the story of "Makalu" Gau Ming-Ho, the leader of a Taiwanese expedition that made the summit attempt alongside Mountain Madness and Adventure Consultants. Gau reached the summit late, encountered difficulty and was left with Scott Fischer and Lopsang Jangbu Sherpa. Gau remained near Fischer when the latter convinced Lopsang to leave him behind. Sherpas later reached the two men, but Fischer was too far gone to save. Gau and Beck Weathers were both helped down the mountain by two other expeditions and eventually airlifted by helicopter. Weathers insisted that Gau be airlifted first as the latter was in far worse shape. The film depicts only Weathers' rescue, omitting the fact that the helicopter pilot actually accomplished his daring high-altitude rescue twice that day.

The film is based on various books about the 1996 Mount Everest disaster, as well as audio recordings from that day. In a September 2015 interview with Entertainment Weekly, Director Baltasar Kormákur confirmed that his film was initially based on the book "Left for Dead", by Beck Weathers, a climber who survived the disaster. He went on to say that Jon Krakauer's book, Into Thin Air, was not used as source material.