What is Wales famous for?

Answer

The Nation of Wales has the longest history in Europe, predating England, for example, by well over two thousand years. Philologically, the language is related to Rhaetian and Etrurian (Etruscan), and standing stones, some over three thousand years old, carved in the old Coelbren (stroke alphabet) script can be found as far afield as Greece, while precursors are found on stones in the Lebanon, and in the Wadi Moqateb and the Djell Moqateb, as discovered many centuries later by Indico Pleustes, and later recorded by the Reverend Charles M. Forster (about 1887). The Welsh language (Cymraeg) is therefore the oldest of all European languages.
Wales has gained the more fleeting fame of modernity for many things, although the pivotal role of Welsh steam coal and Welsh steel should not be underestimated.
A truly beautiful land, Wales boasts mountains and valleys which still occasionally ring to the sound of singing, or the delicate blend of instruments in brass bands. The Welsh Male Voice Choirs (famously Treorchy Male Voice - Cor Meibion Treorci), and the Brass Bands (T. J. (Tom) Powell's Melin Griffith Band and the Cory Band spring to mind as the best of the best) were almost destroyed with the destruction of heavy industry in the valleys by Mrs Thatcher, since the steel manufacturers and the coal mines used to sponsor the music, and highly competitive concerts would take place several times a year.
Despite the modern concentration on Pop music, some of the most beautiful tunes in the world originated in Wales - Myfanwy, Calon Lan, Cwm Rhondda, Blaen Wern and Aberystwyth being good examples, whilst the national anthem - known in English as 'Land of my Fathers' and 'The Old Land of My Fathers' translated from Welsh) could be argued to be the most beautiful national anthem in the world. It doesn't talk of conquest or of war, but of the peace and beauty of the valleys, rivers, forests and streams, and the songs and poetry of the people.
More recently, Wales has produced some powerful popular singers - Harry Secombe, Tom Jones and Shirley Bassey being classic examples, and some well known Hollywood performers of whom Richard Burton is probably the best known, although these days, Catherine Zeta Jones also springs to mind, as does the lovely 'Voice of an Angel' Charlotte Church for a modern singer.
Ivor Novello hailed from Cardiff, and Dylan Thomas is also well known around the world for his beautiful and poetic descriptions of welsh life, whilst the father of the British National Health Service was a Welshman, Aneurin (Nye) Bevan. 
Wales also has some remarkably good breweries for those with a taste for real ale, and although S.A. Brain's is probably the best known, it is not the best beer, since that accolade has now been bestowed upon several smaller breweries. This writer's favourite is The Otley Brewery from Cilfynydd in Pontypridd, where the Otley Arms in Treforest is known affectionately as the 'O' block for Glamorgan University which is just across the road. Ah the lectures I missed! 
While these comments may seem to be - shall we say- South Wales-centric - there is a good and valid reason for this. Although the culture blends across the country, there are distinct differences between those who hale from the north (Gogledd) and those from the south (De). 
These difference actually run much deeper than most people perceive. It would not be misleading to suggest that the 'Gogs' have a distinctly different origin from the South Walian. From an ethnocentric viewpoint, the Gogs are of Celtic origin and their language bears close ties with Eirse and the Scots Gaelic - which I spoke as a boy growing up in the Outer Isles. The softer language of the South is Cymric, deriving from Kymeroi, an insulting name for the Brythonic people from whom they sprang - rather than the  Celts. Hence the language is Brythonic - or British, if you'd rather in its origins! The physiological differences are quite marked: the South Walian is traditionally short and dark: his Gogledd counterpart is raw-boned, scrawny, pale of skin and red of hair, although there are some truly striking blonde women up there! 

History.
Although Wales was never conquered by England, - nor ideed by the Romans - it has always been sadly oppressed by the english, and the adoption by the English royal family (who are technically Germans) of the title Prince of Wales for Prince Charles and many others before him, has never been well received in some quarters. Knowledge of the existence of the old Kingdoms caused the english royal family to try to destroy Welsh culture, and libraries such as Hafod House were burnt to the ground, the language banned and gaol sentences imposed on those who dared to speak their own tongue. Although an MP may quote a phrase from another language in the English Parliament, there is only one language which is totally banned there, and that is Welsh.
The old Kingdoms of Wales predate the anglo saxon usurper - and the later french-danish Normans -  by thousands of years. Probably the most important was the Kingdom of Glamorgan which housed the paramount King, although the Kingdoms of Gwent and of Brecon were also significant. Helen the mother of Constantine who started the Roman Catholic Church was the daughter of Brychan Brycheiniog (Brychan ap Brecon) who was a Christian King, arguably of the Gnostic tradition, and Wales - which was the original Britain long before England was born - had been Christian for some centuries before the Roman Church was invented. King LLeirwg declared Britain for Christ about 156 A.D., but the oldest Christian construction predates that by many years. Churches were named after the Saint who founded them and who was usually found to have been buried there after he or she passed away. This raises an interesting point since Saint Ilid (note: NOT Illtyd) is claimed to have been uncle to Jesus (Ieshua bin Miryam) and better known to us as Joseph of Arimathea. Not far from Bridgend in Glamorgan is the Church of Llanilid. But this is a relatively modern Church being probably less than a thousand years old.
However, standing with one's back to the Church gate and looking to the left, there is a copice atop a steep but not very high hillock. Beyond that is a cup shaped hollow, while to the far side is an ascension path which the Saint would ascend to address the flock who stood below in the hollow. The parish of Christ's uncle!
From a sporting viewpoint, the old County of Glamorgan, now dismantled, has consistently produced a good cricket team, the Cardiff City football team, the Bluebirds, has a strong following, but the national sport is undoubtedly Rugby, and despite the comparatively small population (about a tenth of England's), Wales still frequently manages to beat all comers. England is always the enemy, and passions are always at their highest when the Wales - England matches are played. Because the French also enjoy an historic rivalry with England, there is a bond between Wales and France, and this is strengthened by the Bretons of north western France speaking a language which is very similar to Welsh.
Cardiff, the capital city, is also home to excellent museums, concert halls and Universities.
The Victorian fathers of the city left a wonderful legacy in the way of classic buildings in Cardiff, but mainly in the large number of parks which Cardiff boasts. One of these, Roath Park, boasts a splendid lake which houses an imitation lighthouse, built to commemorate the departure of Captain Scott from Cardiff docks, on his final and fateful journey to the Antarctic.
Sadly, modernisation is steadily robbing the City of its old characterful districts, and soon, there will be no old Cardiff any longer, just a plastic clone of every other city and Tiger Bay, where the pirates like Henry Morgan came, will be just a legend breathed soft upon the Sou'westerly trades which brought the ships to Cardiff docks for thousands of years......
Home of buccaneers, home of pirates, home of poetry, beauty, laughter and song: that is Wales.