 | Oppidum d'EntremontOrt · Aix-en-Provence | Mark Landon | CC BY 4.0 | Original ↗ |
 | OpstandingskerkOrt · Amsterdam | Ceescamel | CC0 | Original ↗ |
 | Optima SignatureOrt · Chicago | TonyTheTiger | CC BY-SA 4.0 | Original ↗ |
 | Oracle TowerOrt · Gold Coast | Shiftchange | CC0 | Original ↗ |
 | Orange County Regional History CenterOrt · Orlando | Ebyabe | CC BY 2.5 | Original ↗ |
 | OrangerimuséetOrt · Stockholm | Holger.Ellgaard | CC BY-SA 3.0 | Original ↗ |
 | Orange Street SchoolOrt · Fayetteville | Apc106 | CC BY-SA 3.0 | Original ↗ |
 | Oranienburger TorOrt · Berlin | Friedrich Albert Schwartz (1836-1906) | Public domain | Original ↗ |
 | OranjehofOrt · Amsterdam | Alf van Beem | Public domain | Original ↗ |
 | OranjesluizenOrt · Amsterdam | Vince de Vries | Public domain | Original ↗ |
 | OranżeriaOrt · Warschau | ZeroJeden | CC BY-SA 3.0 pl | Original ↗ |
 | Oratorio dei BianchiOrt · Palermo | Bjs | CC0 | Original ↗ |
 | Oratorio dei Buonomini di San MartinoOrt · Florenz | Francesco Bini | CC BY-SA 4.0 | Original ↗ |
 | Oratorio dei CrociferiOrt · Venedig | Didier Descouens | CC BY-SA 4.0 | Original ↗ |
 | Oratorio dei FilippiniOrt · Rom | Jensens | Public domain | Original ↗ |
 | Oratorio del CarminelloOrt · Palermo | Stendhal55 | CC BY-SA 4.0 | Original ↗ |
 | Oratorio della Santissima Annunziata (Peretola)Ort · Florenz | sailko | CC BY 2.5 | Original ↗ |
 | Oratorio della VannellaOrt · Florenz | sailko | CC BY-SA 3.0 | Original ↗ |
 | Oratorio di San AndreaOrt · Rom | Lalupa | CC BY-SA 4.0 | Original ↗ |
 | Oratorio di San Bernardino (Pisa)Ort · Pisa | Lucarelli | CC BY-SA 3.0 | Original ↗ |
 | Oratorio di San Giovanni Battista dei FiorentiniOrt · Bologna | Lorenzov79 | CC BY-SA 4.0 | Original ↗ |
 | Oratorio di San Giuseppe (Firenze)Ort · Florenz | sailko | CC BY 2.5 | Original ↗ |
 | Oratorio di San LucaOrt · Florenz | sailko | CC BY-SA 3.0 | Original ↗ |
 | Oratorio di San MicheleOrt · Padua | Filippof | CC BY-SA 3.0 | Original ↗ |
 | Oratorio di San Silvestro in PalatioOrt · Rom | LPLT | CC BY-SA 4.0 | Original ↗ |
 | Oratorio di Santa Maria Addolorata in TrastevereOrt · Rom | Achille Pinelli (1809−1841) | Public domain | Original ↗ |
 | Oratorio di San TiburzioOrt · Parma | Delahay | CC BY-SA 3.0 | Original ↗ |
 | Oratorio di Sant'IlarioOrt · Parma | Parma1983 | CC BY-SA 4.0 | Original ↗ |
 | Oratorio San GiorgioOrt · Padua | sailko, edited by MenkinAlRire | CC BY-SA 3.0 | Original ↗ |
 | oratorio san picrino FirenzeOrt · Florenz | Sailko | CC BY-SA 3.0 | Original ↗ |
| Oratory of CrociferiOrt · Venedig | Didier Descouens | CC BY-SA 4.0 | Original ↗ |
 | Oratory of Rosary of St. Dominic PalermoOrt · Palermo | Bjs | CC0 | Original ↗ |
 | Orbi Yokohama（オービィ横浜）Ort · Yokohama | Thirteen-fri | CC BY-SA 4.0 | Original ↗ |
 | Orchard CourtOrt · London | Philafrenzy | CC BY-SA 4.0 | Original ↗ |
| Orchard Street, LondonOrt · London | Philafrenzy | CC BY-SA 4.0 | Original ↗ |
 | Orczy-kert ZászlórúdOrt · Budapest | Mazarin07 | CC BY-SA 3.0 | Original ↗ |
 | OrdenshusetOrt · Malmö | Hajotthu | CC BY-SA 3.0 | Original ↗ |
 | Ordenshuset BrofästetOrt · Stockholm | Salgo60 | CC BY-SA 4.0 | Original ↗ |
 | Ordway BuildingOrt · Oakland | Mx. Granger | CC0 | Original ↗ |
 | Orebitská 66Ort · Prag | ŠJů (cs:ŠJů) | CC BY-SA 3.0 | Original ↗ |
 | Orecchio di DionisioOrt · Syrakus | Andrew Malone | CC BY 2.0 | Original ↗ |
 | Oregon Historical SocietyOrt · Portland | Steve Morgan | CC BY-SA 4.0 | Original ↗ |
 | Oregon History MuseumOrt · Portland | Steve Morgan | CC BY-SA 3.0 | Original ↗ |
 | Oregon Holocaust MemorialOrt · Portland | ? (sculpture) / EncMstr (photo) | CC BY-SA 3.0 | Original ↗ |
 | Oregon Portland Cement BuildingOrt · Portland | Ian Poellet | CC BY-SA 3.0 | Original ↗ |
 | Oregon Rail Heritage CenterOrt · Portland | Steve Morgan | CC BY-SA 4.0 | Original ↗ |
 | Orenstein & Koppel LoftsOrt · Berlin | Jörg Zägel | CC BY-SA 3.0 | Original ↗ |
 | Organics Sky Garden RomeOrt · Rom | Julio Aprea from Paris, France | CC BY-SA 2.0 | Original ↗ |
 | Orgues de FlandreOrt · Paris | Jeanne Menjoulet from Paris, France | CC BY 2.0 | Original ↗ |
 | Oriel House, Westland RowOrt · Dublin | Fallduff | Public domain | Original ↗ |
 | Oriental Art Museum in VeniceOrt · Venedig | Wolfgang Moroder | CC BY-SA 3.0 | Original ↗ |
 | Oriental Textile MillOrt · Houston | Ed Uthman, Houston, Texas, USA | CC BY 3.0 | Original ↗ |
 | Original Patentees of District of Columbia MemorialOrt · Washington | Daderot | CC0 | Original ↗ |
 | Orlando HausOrt · München | AuHaidhausen | CC BY 4.0 | Original ↗ |
 | Orlando Museum of ArtOrt · Orlando | Ebyabe | CC BY-SA 3.0 | Original ↗ |
 | Orlando Science CenterOrt · Orlando | Marc Averette (talk) | CC BY-SA 1.0 | Original ↗ |
 | Orlí kašnaOrt · Prag | Jan Polák | CC BY-SA 3.0 | Original ↗ |
 | Orlov Bridge - SofiaOrt · Sofia | Boby Dimitrov from Sofia, Bulgaria | CC BY-SA 2.0 | Original ↗ |
 | Ormeley LodgeOrt · London | Reesmf | Public domain | Original ↗ |
 | Ormiston House EstateOrt · Brisbane | Shiftchange | CC0 | Original ↗ |
 | Ormiston MansionOrt · Philadelphia | Brian W. Schaller | FAL | Original ↗ |
 | Oro BistrotOrt · Rom | Vadim Zhivotovsky | CC BY 3.0 | Original ↗ |
 | Oro BistrotOrt · Rom | Mehrshiddoroudian | CC BY-SA 4.0 | Original ↗ |
 | Oro BistrotOrt · Rom | Bradley Weber | CC BY 2.0 | Original ↗ |
 | Oro BistrotOrt · Rom | cisko66 | CC BY 3.0 | Original ↗ |
 | OrphanageOrt · Belgrad | Dungodung | CC BY-SA 3.0 | Original ↗ |
 | Orpheum at the BeaconOrt · Jersey City | Jim.henderson | CC0 | Original ↗ |
 | Orpington War MemorialOrt · London | Ethan Doyle White | CC BY-SA 4.0 | Original ↗ |
 | Országos Múzeumi Restaurálási és Raktározási Központ - nem hivatalos oldalOrt · Budapest | 12akd | CC BY-SA 4.0 | Original ↗ |
 | Országos Pedagógiai Könyvtár és Múzeum - OPKMOrt · Budapest | Misibacsi | CC BY-SA 3.0 | Original ↗ |
 | Országos Színháztörténeti Múzeum és IntézetOrt · Budapest | Vadaro | CC BY-SA 3.0 | Original ↗ |
 | Ortica Da VivereOrt · Mailand | Arbalete | CC BY-SA 3.0 | Original ↗ |
 | Orton Geological MuseumOrt · Columbus | Ibagli | Public domain | Original ↗ |
 | Ortsmuseum AlbisriedenOrt · Zürich | Paebi | CC BY-SA 3.0 | Original ↗ |
 | Ortsmuseum AltstettenOrt · Zürich | Katja Hottingen | CC BY-SA 4.0 | Original ↗ |
 | Ortsmuseum SchwamendingenOrt · Zürich | Gubbia | CC BY-SA 4.0 | Original ↗ |
 | Oruńska StarówkaOrt · Danzig | Oruniak at Polish Wikipedia | CC BY-SA 3.0 | Original ↗ |
 | OrvmOrt · Rom | Fred Romero from Paris, France | CC BY 2.0 | Original ↗ |
 | OrvmOrt · Rom | gnuckx | CC BY 2.0 | Original ↗ |
 | OrvmOrt · Rom | gnuckx | CC BY 3.0 | Original ↗ |
 | OrvmOrt · Rom | Fred Romero from Paris, France | CC BY 2.0 | Original ↗ |
 | Osaka CastleOrt · Osaka | 663highland | CC BY 2.5 | Original ↗ |
 | Osaka City Museum of Fine ArtsOrt · Osaka | 663highland | CC BY 2.5 | Original ↗ |
 | Osaka Museum of Natural HistoryOrt · Osaka | KENPEI | CC BY-SA 3.0 | Original ↗ |
 | Osborne Power StationOrt · Adelaide | Marcus Wong | CC BY-SA 3.0 | Original ↗ |
 | Oscar Anderson House MuseumOrt · Anchorage | 61north | CC BY-SA 4.0 | Original ↗ |
 | Oscar II FortOrt · Göteborg | Saftgurka | CC BY-SA 3.0 | Original ↗ |
 | OscarshallOrt · Oslo | Premeditated | CC BY-SA 4.0 | Original ↗ |
 | Oscar Stanton De Priest HouseOrt · Chicago | Zol87 from Chicago, Illinois, USA | CC BY-SA 4.0 | Original ↗ |
 | Oscar Wilde HouseOrt · Dublin | Rodhullandemu | CC BY-SA 4.0 | Original ↗ |
 | Oscar Wilde Memorial BookshopOrt · New York | GK tramrunner229 | CC BY-SA 3.0 | Original ↗ |
 | Osceola Apartment HotelOrt · Hialeah | Ebyabe | CC BY-SA 3.0 | Original ↗ |
 | Osgoode HallOrt · Toronto | Mikerussell | CC BY-SA 3.0 | Original ↗ |
 | Os. Górczewska-NarwikOrt · Warschau | Andrzej Błaszczak | CC BY-SA 4.0 | Original ↗ |
 | Osiedle Angel WingsOrt · Breslau | vorwerk | CC BY-SA 3.0 | Original ↗ |
 | Osiedle cybernetykiOrt · Warschau | Cybularny | CC0 | Original ↗ |
 | Osiedle im. Józefa Montwiłła-MireckiegoOrt · Łódź | Darekm135 | CC BY-SA 3.0 | Original ↗ |
 | Osiedle Na MurawieOrt · Posen | MOs810 | CC BY-SA 4.0 | Original ↗ |
 | Osiedle PogodnaOrt · Warschau | Cybularny | CC0 | Original ↗ |
 | Osiedle SpektrumOrt · Danzig | Panek | CC BY-SA 4.0 | Original ↗ |