Greece

View of the famous Acropolis of Athens, a World Heritage site atop a rocky outcrop overlooking the modern city of Athens. Construction of its famous Parthenon, a temple dedicated to the city's namesake goddess, Athena, began in 447 BC. It was severely damaged during fighting between the Venetians and Ottomans in 1687. At that time, the British Ambassador to the Ottoman Empire, Thomas Bruce, 7th Earl of Elgin removed some of the sculptures that survived the fighting, with the Ottoman Turks' permission, which lead to the modern-day dispute over the return of the Elgin Marbles, now held in the British Museum.

Permanent rate stamp from 2010 featuring traditional Greek architecture. 

Thanks so much to Molly who sent this card while she was on holiday there!

United States of America – New York

View of Lower Manhattan skyline. Quite an old photo, I think, from the looks of the land reclamation development in the bottom left of the card.

Thanks to Kate, a recent NYC transplant from Singapore, and best of luck to her there! :-)

New international rate stamp depicting Lancaster County in Pennsylvania, the centre of Amish culture in the United States.

Guernsey

Card showing Saint Peter Port, the capital and main city of the British Crown dependency of Guernsey in the Channel Islands, off the coast of Normandy, that has been settled since pre-Roman times. Saint Peter Port was home to Victor Hugo after his exile from France for publishing political treatises against Emperor Napoleon III.

The card was, unfortunately, not sent through the Guernsey postal system, but rather the UK Royal Mail, and sports an unglamourous postage meter stamp.

Algeria II

Multiview showing tiny views of a number of famous sites throughout the country.

Left stamp, issued in 1996, is in honour of Algeria's National Science Day on 16 April. Right stamp, issued in 2007, commemorates Cheikh Mohamed Ameziane Belhaddad, an early resister to the French colonisation of Algeria, born around 1790.

Indonesia II

Vintage postcard showing a kecapi suling traditional Indonesian music ensemble from southern Sulawesi island. 

Stamp from a 2001 set of eight of Flower Greeting stamps.

United Kingdom II

Postcard celebrating Somerset dialect. Somerset and other West Country dialects do not derive from a corrupted form of modern English, but reflect the historical origins of the English language and its historical pronunciation. Interestingly, "pirate speech" of Ooh arr, me 'earties! is in large part derived from West Country dialects, possibly due to the region's seafaring tradition, or also possibly because of the many West Country natives who starred as pirates in productions of The Pirates of Penzance and in Disney movies like Treasure Island and Blackbeard the Pirate. 

Machin Queen's Head first class domestic rate stamps.

Thailand II

Procession of monks at Wat Arun, in Bangkok, for the Tak Bat Devo festival, which marks Buddha's return to Earth after his enlightenment. Monks are offered special food by laypeople in honour of the auspicious day.

Left stamp is a definitive of King Bhumibol, the world's longest serving head of state. Right stamp, from a set of four, was issued in honour of the 2011 Thailand Philatelic Exhibition (Thaipex), and features likae, a traditional style of Thai performance.

France V

Chenonceau Castle, spanning the Cher River in the Loire Valley UNESCO World Heritage site. Built in the sixteenth century, King Henry II offered Chenonceau to his mistress, Diane de Poitiers. When Henry died, his jealous wife, Catherine de' Medici, forced Diane out of Chenonceau, and grew famous for hosting lavish parties here that included the first ever display of fireworks in France. Chenonceau is the most visited château in France after Versailles. 

Purple Mariane in Europe international rate definitive stamp.

Indonesia

Palm-fringed islet off Bintan, an up-and-coming resort destination just a short ferry ride away from Singapore. The Indonesian Government is promoting Bintan as "the next Bali", although I think there may be a long way to go to fill those shoes!

Stamp features an orchid, but could not find any further information about it.

Canada – Alberta II

Famous view of Spirit Island in Maligne Lake in Jasper National Park, part of the Canadian Rocky Mountain Parks World Heritage site. The technicolour turquoise water is the result of glacial runoff. Maligne Lake is the starting point for one of the most renowned hikes in the Rockies, the Skyline Trail, part of which I hiked with my dad and stepmother when I was about eight or ten. 

Canada's 2011 international rate Christmas stamp featuring scenes from the stained-glass windows of the Cathedral of Saint Mary of the Immaculate Conception in Kingston, Ontario, which was built nearly a century and a half ago with windows imported from England. – Incidentally, Canada was the first country in the world to print a Christmas stamp in 1898.