3,546 articles
Rasmussen Lowlands
The Rasmussen Lowlands are a wet tundra coastal plain near the Boothia Peninsula in Nunavut, Canada, designated a Ramsar site in 1982 for up to 500,000 shorebirds.
Ratak Chain
Ratak Chain, the eastern "sunrise" chain of atolls in the Marshall Islands, parallel to the Ralik Chain; includes Majuro, Arno, Wotje, Likiep, and Mili, with 30,925 residents in 1999.
Ravine
Ravine: a small, narrow, steep-sided, V-shaped stream valley larger than a gully and smaller than a canyon; from French ravin and Latin rapina; also a land-degradation feature in India.
Razorback Mtn.
Razorback Mtn. (Razorback Mountain) is a descriptive peak name; in British Columbia it denotes a 2,605 m Rockies border summit near Yellowhead Pass and a 3,183 m ultra-prominent Niut Range (Coast Mountains) peak.
Recheschnoi
Recheschnoi (Mount Recheshnoi) is a 1,984-m glaciated Holocene stratovolcano on Umnak Island in the Aleutians, Alaska, east of Vsevidof, with no historic eruptions and Alaska's only known geysers at Geyser Bight.
Redonda Formation
Redonda Formation: Upper Triassic red-bed unit, uppermost Chinle Group and Dockum Group in New Mexico; lacustrine mudstones and siltstones up to 92 m thick with Apachean tetrapod fauna and ichnofossils.
Registan Desert
The Registan Desert, also written Rēgistān, meaning "land of sand" in Dari, is a largely stabilized red-dune sand sea of about 25,000 km² in southern Afghanistan.
Renaud Island
Renaud Island (Isla Renaud, Île Renaud), largest island of the Biscoe Islands off the west Antarctic Peninsula; ice-covered, 511 km², discovered by Biscoe in 1832, named by Charcot's French expedition after hydrographer M.-J.-A. Renaud.
Rennell Island
Rennell Island, locally Mugaba or Mu Nggava, is a raised coral atoll in the Solomon Islands that UNESCO calls the largest raised coral atoll in the world.
Reo Purgyil (mountain, India)
Reo Purgyil (6,816 m), also confused with Leo Pargial, is the highest peak of Himachal Pradesh, India, on the Tibet border in Kinnaur. First climbed unrecorded by ITBP in 1971; only a handful of ascents since, all via the west ridge from Nako.
Republic of Minerva
The Republic of Minerva was a short-lived libertarian micronation proclaimed January 19, 1972 by Michael Oliver on the Minerva Reefs (Teleki Tokelau, Teleki Tonga), two Pacific atolls, until Tonga annexed them in 1972; the reefs remain disputed between Tonga and Fiji.
Resolution Island (island, Canada)
Resolution Island (Tudjaat) is an uninhabited 1,015 km² island off southeastern Baffin Island, Nunavut, in Davis Strait, named by Thomas Button after his ship; it hosted Cold War Pinetree and DEW Line radar sites and underwent major PCB remediation.
Retreat of glaciers since 1850
Retreat of glaciers since 1850: the near-global shrinkage of mountain glaciers from their Little Ice Age maximum around 1850, accelerating since 1990, with 6,542 Gt of mass lost 2000–2023 and attribution to human-caused warming.
Retrogressive thaw slump
A retrogressive thaw slump, also known as a megaslump, is a slope failure in ice-rich permafrost in which a steep headwall retreats upslope as the ground thaws.
Rhineland
The Rhineland (Rheinland) is a cultural and geographical region of western Germany along the Rhine, not a single administrative unit. Formerly Prussia's Rhine Province, occupied by the Allies 1918–1930, today it spans North Rhine-Westphalia and Rhineland-Palatinate and is a leading German chemical and economic region.
Rhion
Rhion (Ῥίον, Rhium) was an Achaean promontory at the western entrance of the Corinthian Gulf, opposite Antirrhium, with a temple of Poseidon; defended by Phormio in 431-421 BC, now modern Río, Greece.
Rhodes (Ρόδος)
Rhodes (Ρόδος) is the largest Dodecanese island in the southeastern Aegean, 1,401 km² with 125,113 residents. Its city, founded 408 BC, was held by the Knights of St John 1309–1522, then Ottoman and Italian rulers; the Medieval City is a UNESCO site.
Richard Harris (anaesthetist)
Richard 'Harry' Harris SC OAM is an Adelaide anaesthetist and cave diver who sedated and medically cleared the 12 boys rescued from Thailand's Tham Luang cave in 2018, then became joint 2019 Australian of the Year and Lieutenant Governor of South Australia.
Richat Structure
Richat Structure (Guelb er Richât), the Eye of the Sahara: a ~40 km eroded geological dome in Mauritania's Adrar Plateau, a Cretaceous alkaline igneous complex with CAMP gabbro sills (230–200 Ma), not an impact crater, a landmark visible from orbit.
Richland Balsam
Richland Balsam, a 6,410-ft peak near Waynesville, North Carolina, is the highest summit on the Blue Ridge Parkway; its road crosses at 6,053 ft (Milepost 431.4) through threatened red spruce-Fraser fir forest.
Rick Stanton
Rick Stanton (Richard William Stanton, MBE), British cave diver and retired West Midlands firefighter who, with John Volanthen, found the twelve boys trapped in Thailand's Tham Luang cave in 2018; known for Wookey Hole and Ressel exploration records.
Ridley Island
Ridley Island: name of two islands, one off King George Island, South Shetland Islands, Antarctica (charted by Bransfield, 1820), and one near Prince Rupert, British Columbia, named for Bishop William Ridley in 1924.
Rif
Rif (Arrif, الريف): mountainous region of northern Morocco from the Strait of Gibraltar to the Moulouya valley; alpine-type chain under 2,000 m, Tarifit-speaking, about 5 million people; site of the 1921 Republic of the Rif and the 2016–2017 Hirak.
Riiser-Larsen Peninsula
Riiser-Larsen Peninsula (Riiser-Larsenhalvøya), also called Cook Peninsula, is a large peninsula in Dronning Maud Land, East Antarctica, at 68°55'S 34°00'E, forming the western portal to Lützow-Holm Bay and separating the Princess Ragnhild and Prince Harald Coasts; discovered by Hjalmar Riiser-Larsen from the Norvegia on 21 February 1931.
Rikers Island
Rikers Island: 415-acre New York City jail complex in the East River between Queens and the Bronx, operated by the DOC since 1935; bought in 1884, now slated for closure by 2027 under federal oversight.
Rila (Рила)
Rila (Рила) is Bulgaria's and the Balkan Peninsula's highest mountain, 2,925 m at Musala, 2,396 km² in southwestern Bulgaria, with LGM glaciation, Rila National Park, and the UNESCO Rila Monastery.
Rimstone
Rimstone, also called gour, is calcareous (usually calcite) deposit forming dams around overflowing cave pools and springs. Dams grow as CO2 outgassing at the turbulent rim precipitates calcite, ranging from 1 mm microgours to over 12 m.
Ringvassøya
Ringvassøya (Ráneš) is Norway's sixth largest mainland island, 661 km², in Tromsø and Karlsøy municipalities north of Tromsø, linked by the Kvalsund Tunnel, with Hansnes as Karlsøy's administrative center.
Risco Plateado
Risco Plateado (Cerro Risco Plateado), a 4,999 m stratovolcano with a 4-km caldera in Malargüe Department, Mendoza, Argentina, Southern Andean Volcanic Arc; no known Holocene eruptions, Plio-Pleistocene volcanics.
Rising Star Cave
Rising Star Cave, in South Africa's Cradle of Humankind near Johannesburg, is the cave system where Homo naledi fossils were found in 2013: over 1,550 specimens from at least 15 individuals in the Dinaledi Chamber, dated 335,000 to 236,000 years old.