6,162 articles
Oruro (city)
Oruro, city in western Bolivia, capital of Oruro department, founded 1606 as Villa San Felipe de Austria; 3,700 m Altiplano mining (tin) city, home of the UNESCO-listed Carnival of Oruro, distinct from the department of the same name.
Orvieto
Orvieto, ancient Etruscan Velzna (Volsinii), is an Umbrian hill town in Italy on a 150-metre tufa cliff, known for its Gothic cathedral begun in 1290, about 1,200 underground caves, St. Patrick's Well, and Orvieto DOC wine.
Osaka (大阪)
Osaka (大阪) is a major Japanese port and commercial city in Kansai, population about 2.81 million, Japan's ancient gateway to Asia, Edo-period "Kitchen of Japan," site of Osaka Castle, and host of the 1970 and 2025 World Expos.
Osan
Osan (오산시, 烏山市) is a city in southwestern Gyeonggi Province, South Korea, between Suwon and Pyeongtaek, about 60 km from Seoul. Promoted from Osan-eup to city status on 1 January 1989, it is a residential satellite city of over 200,000 people, distinct from Osan Air Base, which lies in Pyeongtaek.
Osh
Osh (Ош) is Kyrgyzstan's second-largest city, in the eastern Fergana Valley at the Ak-Buura river, a 3,000-year-old Silk Road hub with UNESCO-listed Sulaiman-Too; 333,629 residents (2022), 700 km from Bishkek.
Oshawa
Oshawa, Ontario, is a city on Lake Ontario in Durham Region about 60 kilometers east of Toronto, historically known as Canada's Motor City for its General Motors automobile industry.
Oshkosh, Wisconsin
Oshkosh, Wisconsin: city on Lake Winnebago's western shore in Winnebago County, named for Menominee chief Oshkosh. Lumber-era "Sawdust City," home of Oshkosh Corporation, OshKosh B'Gosh, UW-Oshkosh, and EAA AirVenture, the world's largest fly-in.
Osijek
Osijek (German Essegg, Hungarian Eszék) is Croatia's fourth-largest city, on the Drava River in eastern Slavonia; Roman Mursa, baroque Tvrđa, seat of Osijek-Baranja County, 75,535 residents (2021), noted for a high quality-of-life to cost-of-living ratio.
Oslo
Oslo (Oslove) is the capital and largest city of Norway, a municipality and county at the head of the Oslo Fjord with about 728,700 inhabitants in 2026, founded around 1000 AD, renamed Christiania 1624–1925, with a parliamentary city government since 1986.
Osmaniye (city)
Osmaniye, city in southern Turkey, seat of Osmaniye Province on the Ceyhan River plain. Province population 564,123 (2025), 83.63% urban; first-degree earthquake zone on the East Anatolian Fault; 2023 quakes damaged thousands of buildings.
Osnabrück
Osnabrück is a German city in Lower Saxony on the River Hase, founded by Charlemagne in 780, a former Hanseatic town and site of the 1648 Peace of Westphalia, with about 165,000 inhabitants.
Osogbo
Osogbo (Oṣogbo, Oshogbo), capital of Osun State, Nigeria, at 7°46′N 4°34′E; a Yoruba commercial city on the Lagos-Kano railway, home of the Ataoja ruler, the Osun-Osogbo Festival, and the UNESCO-listed Sacred Grove.
Osoyoos
Osoyoos, British Columbia: a border town on Osoyoos Lake in the South Okanagan, named from the Syilx word soo-yoos. Canada's warmest fresh-water lake, only desert, wine and fruit economy, incorporated 1946, town 1983.
Ostend
Ostend (Oostende, Ostende), Belgium's largest coastal city in West Flanders: 73,000 residents, 7 km beach, 658 ha port, railway terminus, James Ensor's home city, and a focal point of Flemish coastal flood defense.
Osterøy
Osterøy: municipality and island in Vestland county, Norway, northeast of Bergen. Island area 330 km², Norway's largest inland island surrounded by saltwater; municipality formed 1964 from Haus, Hamre, Hosanger, Bruvik; center Lonevåg, population about 8,200.
Ostrava
Ostrava, Czech statutory city and Moravian-Silesian Region capital, third largest Czech city by area and population; former coal and steel center, now services, universities, and Dolní Vítkovice industrial heritage.
Ostrov
Ostrov, a commune in Constanța County, Romania, holds the Roman civil settlement of Durostorum at Ferma 4 and the Byzantine island fortress Păcuiul lui Soare; other Ostrov place names exist in Latvia, Czechia, and Russia.
Oswaldtwistle
Oswaldtwistle is a Lancashire town between Blackburn and Accrington, home of James Hargreaves' 1764 Spinning Jenny and a major cotton and calico-printing centre, now known for Oswaldtwistle Mills shopping village.
Oswestry
Oswestry (Croesoswallt) is Shropshire's second largest market town, near the Welsh border on the A5. Known for Old Oswestry hillfort, the 1190 market charter, Cambrian Railways headquarters, and poet Wilfred Owen's birthplace.
Oświęcim
Oświęcim (German: Auschwitz) is a town of about 35,000 in southern Poland, in Małopolska, with 800 years of recorded history; it is known worldwide as the site of the Nazi German Auschwitz concentration and extermination camp, now the Auschwitz-Birkenau State Museum.
Ōta-ku
Ōta-ku (大田区), a special ward in southeastern Tokyo formed 15 March 1947 by merging Ōmori and Kamata wards; largest of the 23 wards at 61.86 km², home to Haneda Airport, the Keihin industrial belt, and the Ōmori shell mound.
Ōta, Gunma
Ōta (太田市, Ōta-shi) is a city in southeastern Gunma Prefecture, Japan, population about 222,000. Formed 2005 by merger; former Nakajima Aircraft site, now home to Subaru's Gunma plants and Gunma's top industrial output.
Ota, Ogun State
Ota (Otta), town in Ado-Odo/Ota LGA, Ogun State, Nigeria, north of Lagos; Awori town under the Olota of Ota; 163,783 residents (2006); major industrial hub with Covenant and Bells universities.
Otavalo
Otavalo is a town and canton in Imbabura province in the northern Ecuadorian Andes, best known for its large indigenous textile market and Kichwa-Otavalo craftspeople.
Ōtsu
Ōtsu (大津市) is the prefectural capital of Shiga Prefecture, Japan, a core city on Lake Biwa near Kyoto with about 342,700 residents; it was Japan's capital 667–672 and part of the UNESCO Ancient Kyoto site.
Ottawa
Ottawa, Canada's capital in eastern Ontario, grew from Bytown, founded with the Rideau Canal in 1826, and was chosen as capital by Queen Victoria in 1857. It hosts the federal government, over 1,900 tech firms, and ranked first in North America in Numbeo's 2026 quality of life index.
Ouagadougou
Ouagadougou (Ouaga) is the capital and largest city of Burkina Faso, population 2.5 million in 2015, founded by the Mossi in the 12th century, on the Abidjan railway, facing rapid growth, sanitation gaps, and extreme Sahel heat.
Oualata
Oualata, also spelled Walata (Arabic ولاته), is a historic fortified town in southeastern Mauritania that served for centuries as the western terminus of the Saharan trade route from Timbuktu.
Ouargla
Ouargla (Arabic ورقلة) is an oasis city and provincial capital in the Algerian Sahara, near the Hassi Messaoud oil fields, with a 6,000 ha palm grove, a historic walled ksar, and a university founded in 1988.
Ouarville
Ouarville is a commune in the canton of Voves, Eure et Loir, France, with 548 inhabitants. Located in the Beauce plain southeast of Chartres, it has a rich recorded history.