Europe

Armenia:
Yerevan Cascade (Yerevan)

Austria:

Rogner Bad Blumau (Bad Blumau)

Surreal Lawn-House (Frohnleiten)
Kunsthaus Graz (Graz)

Apocalypse Chapel (Klagenfurt)
Hundertwasser-Haus (Vienna)
Müllverbrennungsanlage Spittelau (Vienna)

KunstHaus Wien (Vienna)

Otto Wagner / Ernst Fuchs Villa (Vienna)
Secession (Vienna)
Bar Rectum (Vienna)
Swarovski Kristallwelten (Wattens)

Belgium:

The Invisible Church (Borgloon)
Dinner in the Sky (Brussels)
Hotel Tassel (Brussels)

6 rue du Lac (Brussels)

Châtillon Car Graveyard (Châtillon)
Château Miranda - Château de Noisy (Celles)
La Balade des Gnomes (near Durbuy)
Tower of the Apocalypse (Eben-Emael)

The house of James Ensor (Ostend)

B-and-Bee Honeycomb Tents

Bosnia and Herzegovina
Sanski Most Spomenik (Sanski Most)

Bulgaria:

Abandoned Bulgarian Communist HQ (Buzludzha)
Rila Monastery (Rila Mountains)

Snail House (Sofia)

Croatia:
Jasenovac monument (Jasenovac)

Czech Republik:

Sedlec Ossuary (Kutná Hora)

The Dancing House (Prague)

Denmark:

Rainbow Panorama Walkway (Arhus)
Hotel Fox (Copenhagen)
Stained-glass house (Copenhagen)

 

Finland:

Palace of dreams (Helsinki)

Moomin House (Naantali)
Hotel & Igloo Village (Saariselkä)

Garden Shed turned Glass Bedroom

France:

Oak chapel (Allouville- Bellefosse)

Gainza Treehouse (Biarritz)
La Maison Picassiette (Chartres)

Le jardin de nous deux (Civrieux d'Azergues)
(Colmar)

Musée Robert Tatin (Cossé-le-Vivien)

51 Rue Jean Bellegambe (Douai)
Ferdinand Cheval's Palais Idéal (Drôme)

Flower restaurant Mas Provençal (Èze)
The house and garden of Claude Monet (Giverny)

Jardins Secrets (Haute-Savoie)
Les Ecotagnes Treehouse (Haute-Savoie)
Maison Coilliot (Lille)

La Maison Cassee Vaisselle (Louviers)
Lyons-satolas TGV station (Lyons)

Bubble Tent Hotel (near Marseille)
Le Cyclop (Milly-la-Forêt)
Central Nice Library (Nice)

Cunégonde et Malabar (Nice)
Les Mystères du Nautilus (Disneyland Paris)

Cafe de L'Enfer (used to be in Paris)

29 Avenue Rapp (Paris)

Quai Branly Museum (Paris)

Palais Royal Metro Station (Paris)

Postmodern Utopian Dream City (Paris)

Sainte Chapelle (Paris)

Reconstruction of the Fouquet Boutique (Paris)

Painted house (Paris)

Patrick Blanc's Home (Paris)
Manish Arora's apartment (Paris)

La maison de Celle-Qui-Peint (Pont-de-l'Etoile)
Gardens of Marqueyssac (Vézac)

Germany:

Hundertwasser-Kuchlbauer Tower (Abensberg)
AquaDom (Berlin)
Propeller Island City Lodge (Berlin)

Rettungsturm (Binz auf Rügen)

Base Camp Bonn Young Hostel (Bonn)
Waldspirale (Darmstadt)
Kunsthofpassage Funnel Wall (Dresden)
Julius Klingebiel Zelle (Göttingen)
Neuschwanstein Castle (Hohenschwangau)

Lichtenstein Castle (Honau)

Faces along the Path (Landstuhl)

Das Junkerhaus (Lemgo)

Baumraum's World of Living Tree House (Rheinau-Linx)
V8 Hotel (Stuttgart)
Upside-down house (Trassenheide)

Baumhaus Solling (Uslar)
Giant Lego Bridge (Wuppertal)
Rainbow Staircase (Wuppertal)

Greece:
Meteora Monasteries (near Kalambaka)

Hungary:
Lutheran Church (Siofok)

Iceland:

Lonely house (Elliðaey)

Hallgrímskirkja - Church of Hallgrimur (Reykjavík)

Italy:

The conic "Trulli" dwellings (Apulia)

Villa Lante water gardens (Bagnaia, near Viterbo)

Park of the Monsters (Bomarzo)

Colourful tower houses on Liguria's coast 
Cave dwellings (Sassi di Matera)
Bosco Verticale - Vertical Forest (Milan)
The Forgotten Palazzo (Milan)
La Scarzuola (Montegabbione)
Toledo Metro Station (Naples) 
Villino Ruggeri (Pesaro)
Villa Sbertoli - Abandoned Psychiatric Hospital (Pistoia)
Castello di Sammezzano (Reggello)
Casina delle Civette at Villa Torlonia Park (Rome)

Cimitero dei Cappuccini (Rome)

Casa Fenoglio-La Fleur (Turin)

San Galgano Abbey (Tuscany)

The Tarot Gardens (Tuscany)

The Tower of Peretti (Tuscany)

The Temples of Damanhur (Valchiusella)
Burano Island (near Venice) 

Lithuania:

Office Center 1000 ( Kaunas)
Hill of Crosses (Šiauliai)

Macedonia:
Makedonium (Kruševo)

Netherlands:

WoZoCo Apartments (Amsterdam)

Glow in the Dark Bicycle path (Eindhoven)
Excalibur (Groningen)
Bolwoningen (Hertogenbosch)

The Efteling (Kaatsheuvel)

Keukenhof Tulip Gardens (Lisse)
Beukelsblauw (Rotterdam)

Kubuswoningen - Cubic houses (Rotterdam)
Bunker Pavilion Holiday Home (Vuren)
Inntel Hotel (Zaandam)

Norway:

Igloo hotel (Alta)
Holmenkollen - Penthouse on a Ski Jump (Oslo)
Lærdal Tunnel (Sogn og Fjordane)

Stauran Art Café (Syltefjord)

Poland:

The Crooked Forest (near Gryfino)
The crooked house (Sopot)

Upside-down house (Szymbark)
A Painted Village (Zalipie)

Portugal:

Striped houses of Costa Nova (Costa Nova do Prado)
House of Stone (Fafe mountains)

Giant Boulder Village (Monsanto)

Pena Palace (Sintra)

Livraria Lello (Porto)

The Initiation Wells of Quinta da Regaleira (Sintra)

Romania:

Merry Cemetary (Săpânţa)

Russia:
 (for the Asian part click here: Asia)

World's tallest log cabin (Arkhangelsk)

Astashovo Ornate Mansion (near Chukhloma)
Abandoned & rescued Folk-style Cottage (near Chukhloma)
Kizhi Island (Karelia)
Monastery under the lake (Kalyazin)
Orthodox Church (Kemsky)
Moscow metro stations (Moscow)

Cube House with Triangular Windows (outside Moscow)
Tiny church on island (near St. Petersburg)

Spain:

Bellesguard (Barcelona)
Casa Batlló (Barcelona)
Casa Calvet (Barcelona)

Casa Milà - La Pedrera (Barcelona)

Casa Vicens (Barcelona)

Palau Güell (Barcelona)

Park Güell (Barcelona)

Old Cement Factory Home (Barcelona)

Palau de la Música Catalana (Barcelona)
13 Plaça del Sol (Barcelona)
Basque Health Department HQ (Bilbao)
Castillo de las Cuevas (Cebolleros)
El Capricho (Comillas)

Dali Museum (Figueres)

Capricho de Cotrina (Los Santos de Maimona)
Kaos Temple (Polígono de Asipo)
Casa Navás (Reus)

Tenerife Concert Hall (Santa Cruz)
Metropol Parasol (Seville)
City of Arts and Sciences (Valencia)

Sweden:

Dragspelhuset (Glaskogen)

Kuggen (Göteborg)
Homeless Experience Hotel (Göteborg)
Tree Hotel (Harads)
The original Ice Hotel (Jukkasjärvi)

Emporia Shopping Center (Malmö)
Turning Torso (Malmö)

Mine- Suite (Sala)
Kolarbyn Ecolodge (Skinnskatteberg)
Stockholm Metro (Stockholm)
Hotel Hackspett - Woodpecker hotel (Västerås)

Switzerland:

Tschuggen Grand Hotel (Arosa)
Residential House Vetsch (Dietikon)
Earth House Estate Lättenstrasse (Dietikon)
Schtroumph Buildings (Geneva)
HR Giger Bar (Gruyères)
Church of St John (Mogno)
Skulpturenpark (Spreitenbach)
Residential House Dolder (Widen)
The Blur Building (Yverdon-les-Bains)

Ukraine:

A Ukrainian Hogwarts (Chernivtsi)
The Swallows Nest (Gaspra)
House with Chimeras (Kiev)

Tunnel of Love (Kleven)
Floating House (Krasnosilka)
Cave Monastery (Rozgirche)

Polina Rajko's house (Tsuriupinsk)

Druzhba Holiday Center Hall (Yalta)

United Kingdom:

Exbury Egg (Beaulieu river)
Selfridges - Future systems (Birmingham)

Miniature Village (Bourton-on-the-Water)

The Cement Menagerie (Branxton)
The Royal Pavillion (Brighton)

The Eden project (Cornwall)

The Garden of Cosmic Speculation (Dumfries)

Kelburn Castle (Fairlie)
Heart shaped forest (Gloucestershire)
Harlaxton Manor (Harlaxton)

Bombay Sapphire Distillery Glasshouses (Laverstoke)

The Pavilion Hotel (London)
Athenaeum Hotel (London)
Craig Masson & Andrew McMinn's home (London)

The Hardy Tree (London)
Karma Taxis (London)

Sketch (London)
Zandra Rhodes' apartment (London)

Pet Cemetery in Hyde Park (London)

The Dinosaurs of Crystal Palace (South London)
Shell Grotto (Margate)

The Sliding Facade House (Margate)
Pastel Beach Huts (Mersea Island)
The Sage (Newcastle)
Dragon shaped hedge (Norfolk)
Little retreat (Northamptonshire)

Alnwick Garden (Northumberland)

Prison Hotel Oxford Castle (Oxfordshire)

Little castle (Pitlochry)

Portmeirion
Amberley Castle Treehouse (Sussex)

Jack Sparrow House (St. Keverne)
Tree Sparrow House (St. Keverne)
A low impact Woodland Home (Wales)
La Rosa Campsite Extraordinaire (Whitby)

For countries like Turkey etc see the continent's page "Asia"