Question: Makalu and K2 are both what?

Context paragraphs:
Carlos Soria Fontán: Carlos Soria Fontán (Ávila, Spain, February 5, 1939) is a Spanish mountain climber who, at 77 years of age, has taken up the challenge of becoming the oldest person in the world to reach the summits of the 14 highest mountains in the world.  He is the only mountaineer to have ascended ten mountains of more than 8,000 meters after turning 60, and he is the oldest person in history to have successfully climbed the K2 (65 years old), Broad Peak (68), Makalu (69), Gasherbrum I (70), Manaslu (71 years old), Kanchenjunga (75 years old) and Annapurna (77 years old).

Tatra K2: The Tatra K2 was the first production articulated tramcar built by ČKD Tatra between 1966 and 1983, following the failure of the experimental K1 which never entered production.  It was noted that the main problem with the K1 was with the new electrical equipment, and therefore the same electrical equipment of the T3 was incorporated into the new K2.  The prototype entered service in 1966 as Prague tramcar number 7000, where it spent only a short spell before being transferred to Most, and then again moved to Brno.  Production of the K2 on a mass scale started the same year, and many examples remain in service to this day, albeit most having been extensively modernised.  The modernisation of the K2 fleet in Brno, the biggest customer of the type, included the complete re-modelling of the front end, and the upgrading of their electronic equipment.  These modernised examples were labeled K2R, whereby the 'R' stands for 'reconstructed'.

2008 K2 disaster: The 2008 K2 disaster occurred on 1 August 2008, when 11 mountaineers from international expeditions died on K2, the second-highest mountain on Earth.  Three others were seriously injured.  The series of deaths, over the course of the Friday ascent and Saturday descent, was the worst single accident in the history of K2 mountaineering.  Some of the specific details remain uncertain, with different plausible scenarios having been given about different climbers' timing and actions, when reported later via survivors' eyewitness accounts or via radio communications of climbers who died (sometimes minutes) later in the course of events on K2 that day.

K2 Snowboards: K2 Snowboards are snowboards manufactured by the sports equipment, company K2 Sports.  K2 Sports was founded by businessman Bill Kirschner in 1962.  K2 Sports manufactured some of the first sets of fibreglass skis in the 1960s.  K2 delivered its first lot of 250 pairs of fibreglass skis in 1964.  In 1976, the company was acquired by investment company, Sitca.  In 1985 it was acquired by Anthony Industries.  By 1988 the demand for snowboards was high, and by 1994, in a new factory, K2 had produced its own line of snowboards.  K2 became one of the top 5 manufacturers of snowboards in the United States and it has sponsored a number of professional snowboarders including Gretchen Bleiler.

Michael Groom (climber): Michael Groom (born 1959) is an Australian mountain climber.  In 1995, Groom became the fourth person ever to summit the four highest mountains in the world (Lhotse, Kangchenjunga, K2 and Everest) without the aid of bottled oxygen.  He proceeded to climb the fifth-highest, Makalu, in 1999.  In 1987 he lost the front third of his feet to frostbite descending from his successful summit of Kangchenjunga.  Despite this, he later managed to summit Mount Everest in 1993 and again in 1996.  He acted as a guide for Adventure Consultants during the 1996 Mount Everest disaster, of which he survived subsequently referencing in his 1997 autobiography.  In the 2015 film "Everest", Groom was portrayed by actor Tom Wright.

K2: K2 (Urdu: ‎ ), also known as Mount Godwin-Austen or Chhogori (Balti and Urdu: ‎ ), is the second highest mountain in the world, after Mount Everest, at 8611 m above sea level.  It is located on the China-Pakistan border between Baltistan, in the Gilgit-Baltistan region of northern Pakistan, and the Taxkorgan Tajik Autonomous County of Xinjiang, China.  K2 is the highest point of the Karakoram range and the highest point in both Pakistan and Xinjiang.

K2 Black Panther: The K2 Black Panther (Hangul: K2 '흑표'; Hanja: K2 '黒豹') is a South Korean main battle tank that will replace most of the M48 Patton tanks and complement the K1 series of main battle tanks currently fielded by the Republic of Korea.  Mass production commenced in 2013 and the first K2s were deployed with the armed forces in June 2014.  The K2 costs over US$ per unit.

K2 High Definition: K2 technology is an audio mastering technology developed by JVC Kenwood Victor Entertainment Corporation.  It was named after the two engineers who developed the system: Kuwaoka and Kanai.  K2 technology has two major features: Improving sound quality and packing high-definition data in lower format CD.  The fundamental principle of K2 technology is to produce audios that are "closer to the musical truth" and "restoring sound to its original state."  Originally developed from a project in 1987, K2 technology is the fundamental technology of audio mastering technology such as netK2 and K2HD mastering.

Barun Valley: Barun Valley (बरुण उपत्यका ) is a Himalayan valley situated at the base of Mt. Makalu in the Sankhuwasabha district Nepal.  This valley lies entirely inside the Makalu Barun National Park.

Makalu: Makalu is the fifth highest mountain in the world at 8485 m .  It is located in the Mahalangur Himalayas 19 km southeast of Mount Everest, on the border between Nepal and China.  One of the eight-thousanders, Makalu is an isolated peak whose shape is a four-sided pyramid.

Supporting paragraphs: Makalu K2
Answer: mountain