Bhutan's mountaintop monasteries - a trip into timelessness

vibrate. A bassy trumpet sounds again, sending out more tremors, then the rest of the orchestra joins in: funereal drums, crashing cymbals, chanting and, over the top of it all, wailing trumpets made from human thigh bones.

The musicians are all red-robed, shaven-headed monks sitting cross-legged in the hallway of Punakha Dzong, Bhutan's holiest fortress and monastery. They make a powerful sound. "When they play very loudly, that means they're chasing away the negative forces," says my guide, Tshewang Penjor.

We've arrived early at the (monastery). A few younger monks join me on the balcony, also curious to watch and listen to the strange, fascinating ceremony of music and prayer. It feels, like many things in Bhutan, that what I'm seeing and hearing is exactly the same as it's been for centuries.

Tradition and religion are both important to the people of Bhutan. The country runs according to principles of Gross National Happiness - GNH rather than GDP. One of the main pillars of GNH is preserving the country's national dress, architecture, language, religion and culture.

Although the government opened the country up to tourism in 1974, it has resisted mass tourism which it fears might have a negative impact on the country. This means the nation has maintained its character.

Punakha Dzong was formerly the seat of government. More recently, the country's popular king and queen were married here. Now, it serves as the winter residence for the chief abbot and about 1,000 monks. There's a flurry of excitement as we arrive.