Castle Stalker, Appin, Argyll, Scotland

Sigmaringen Castle in Autumn, Baden-Wurttemberg, Germany

Sigmaringen Castle in Autumn, Baden-Wurttemberg, Germany

Chillon Castle (Chateau de Chillon) on shores of Lake Geneva with the Alps in background, Montreux, Vaud, Switzerland

Sunset over Assisi, Perugia province, Umbria, Italy, Europe

Sunset over Assisi, Perugia province, Umbria, Italy, Europe

Georgia, Tbilisi, Old Tbilisi or Dzveli Kalaki, Abanotubani district or district of the sulfur baths dominated by Narikala fortress

India, Madhya Pradesh, Gwalior, Gwalior Fort, Man Singh Palace

Castle Bran, Draculas castle, Bran, Transylvania, Romania

France, Eure, Les Andelys, Chateau Gaillard, 12th century fortress built by Richard Coeur de Lion, Seine valley (aerial view)

Rabati Castle, Akhaltsikhe, Samtskhe-Javakheti region, Georgia.

France, Seine et Marne, Blandy les Tours, the castle (aerial view)

France, Seine et Marne, Blandy les Tours, the castle (aerial view)

France, Doubs, La Cluse et Mijoux, the fort of Joux (aerial view)

France, Cotes d'Armor, Plevenon, Fort la Latte or Roche Goyon castle, is a 14th century fortress at the Pointe de la Latte, close to Frehel Cape

Castle of the Teutonic Order in Malbork, Pomeranian Voivodeship, Poland

Portugal, Lisbon, the castle Sao Jorge overlooks the city

Germany, Baden Wurttemberg, Upper Swabia (Schwäbische Alb), Sigmaringen, Sigmaringen Castle, a Hohenzollern castle, royal residential palace and administrative seat of the Princes of Hohenzollern-Sig...

Germany, Baden Wurttemberg, Upper Swabia (Schwäbische Alb), Sigmaringen, Sigmaringen Castle, a Hohenzollern castle, royal residential palace and administrative seat of the Princes of Hohenzollern-Sig...

Historic Incan Machu Picchu on mountain in Andes, Cuzco Region, Peru

The Clock Tower, dating back to the 14th century, defends the main gate to the citadel of the medieval old town. Sighisoara, Transylvania. Romania

Gaeta at sunset. Europe, Italy, Lazio, Latina province, Gaeta

Aerial view at Stahleck castle with river Rhine at Bacharach, Rhine valley, Rhineland-Palatinate, Germany

St. Michael's Fortress and Sibenik Harbour, Sibenik, Dalmatian Coast, Croatia

Trogir Harbour at Night, Trogir, Dalmatian Coast, Croatia

India, Madhya Pradesh, Gwalior, Gwalior Fort, Man Singh Palace

India, Madhya Pradesh, Gwalior, Gwalior Fort, Man Singh Palace, Elephant Gate (Hathiya Paur)

Toledo and the Tagus river at twilight, a Unesco World Heritage Site. Castilla la Mancha, Spain

India, Rajasthan, Jaipur, Amber, Amber Fort and Wall Fortifications

UK, England, Dorset, Corfe Castle at sunrise

Italy, Umbria, Perugia district, Trevi.

Italy, Umbria, Perugia district, Trevi.

Ota Darvoza, the western gate to the old town of Khiva. A UNESCO World Heritage Site, Uzbekistan

View from Baluarte de Santa Llucia to D'Alt Vila, Ibiza, Balearic Islands, Spain

Church of Elkomenos Christos and Bell Tower in Platia Dsami Square, Monemvasia, Laconia, The Peloponnese, Greece (MR)

Uk, Wales, Gwynedd, Harlech, Harlech Castle, Mountains of Snowdonia National Park beyond

Uk, Wales, Gwynedd, Harlech, Harlech Castle, Harlech Beach and Llyn Peninsula across Tremadog Bay

UK, England, Shropshire, Ludlow, St Laurence's Church at Sunrise

UK, England, Shropshire, Ludlow, Ludlow Castle at Sunrise

UK, England, Shropshire, Ludlow, Ludlow Castle and St Laurence's Church at Sunrise

Albarracin town at dusk. Albarracin, Teruel, Aragon, Spain

Republic of San Marino, Repubblica di San Marino San Marino. Torre Guaita, Pirma Torre, La Rocca.

Italy, Emilia-Romagna Rimini district San Leo

Republic of San Marino, Repubblica di San Marino San Marino. Seconda Torre also known as La fratta or La Cesta

City walls. Ark fortress, Bukhara, a UNESCO World Heritage Site. Uzbekistan

The main gate to the Khuna Ark citadel and the Kalta Minor minaret. Old town of Khiva (Itchan Kala), a Unesco World Heritage Site. Uzbekistan

Ota Darvoza, the western gate to the old town of Khiva, at dusk. In the right side, the Mohammed Amin Khan madrasah and the Kalta Minor minaret. A UNESCO World Heritage Site, Uzbekistan

The old town of Khiva (Itchan Kala), a Unesco World Heritage Site, seen from the Khuna Ark citadel. Uzbekistan

Brazilian Model walking on the Farol da Barra Beach, Salvador, State of Bahia, Brazil (MR)

Munot fortress and vineyards, Schaffhausen, Switzerland.

Hohenzollern Castle, Hechingen, Baden-Württemberg, Germany.

Hohenzollern Castle, Hechingen, Baden-Württemberg, Germany.

Hohenzollern Castle, Hechingen, Baden-Württemberg, Germany.

Liechtenstein Castle, (Württemberg), Reutlingen, Baden-Württemberg, Germany.

France, Eure, Les Andelys, Chateau Gaillard, 12th century fortress built by Richard Coeur de Lion, new look after several years of renovation, Seine valley (aerial view)

France, Corsica, Bonifacio, the Citadel

France, Doubs, La Cluse et Mijoux, the fort of Joux

France, Haute Vienne, Dournazac, the castle of Montbrun

Sirmione, lake Garda, Brescia province, Lombardy, Italy. High angle view of the old town at sunset.