By Alastair Lawson
BBC News, Dhaka
Bangladesh is a country not renowned for its mountain biking terrain
A new sport has emerged in a country which has a reputation for being one of the flattest in the world - mountain biking in Bangladesh.
The activity is growing in popularity in the south-eastern Chittagong Hill Tracts, a predominantly tribal area bordering Burma.
This is no weekend jaunt through pleasant forestry. Riders have to cope with intense humidity, thick jungle, the danger of malaria and poisonous snakes.
But at least it's safer than riding a bike in one of the country's big cities, where it's generally accepted that cyclists have a short life expectancy.
"Bangladesh may only have a few hills where mountain biking is possible," says enthusiast Salman Saeed, "but it is a sport that is really taking off.
"For some time now, younger people in particular have been trying their hand at adventure sports. Recently a group of young boys attempted for the first time to scale one of the highest peaks of Bangladesh - called Kewkardong at about 1,000m (3,400ft) - with their mountain bikes.
It is not always easy-going in the hill tracts
"And despite numerous obstacles, they succeeded. The most difficult part of the trip was the fact that the bicycles they used were weak and needed to be repaired throughout the trip."
The sport is proving to be most popular in Bandarban, part of the Chittagong Hill Tracts, where riders receive local support when crossing various parts of the River Sangu from the local tribal community.
"The roads in the hill tracts are mostly used by locals on foot, and occasionally by trucks carrying logs from the forest," explained Mr Saeed.
"Riding a bicycle is not a common scenario for these local tribal people. When passing through these small villages the kids thought that some alien riders had entered their territory!"
The cyclists are frequently invited into the houses of local people for meals where they are encouraged to explain how their bikes work.
All this would have been inconceivable even five years ago, when the Chittagong Hill Tracts remained heavily militarised despite the signing of the peace treaty in 1997.
The treaty brought an end to a 20-year insurgency waged by tribal people who were unhappy about the influx of Bengali settlers to what they saw as their ancestral homelands.
In a sign of lowering of tension in the area, last July the government withdrew three battalions of troops from the region.
Although there have been signs of unrest bubbling beneath the surface, the hill tracts have mostly remained peaceful with no kidnappings of tourists and government officials that plagued the area 10 years ago.
Now cyclists like Mr Saeed are hoping to take their sport to other parts of rural Bangladesh.
"This is a new sport in a very crowded country where road safety is far from exemplary," said Mr Saeed.
"So the future of the sport in Bangladesh remains very much unwritten. But there is no adventure without difficulties!
"Because large parts of the hill tracts are yet to be explored we have formed a community of young cycling enthusiasts called Kewkradong Bangladesh.
"The name is taken from the local Bowm language - in gratitude towards the help and hospitality we have received from the ethnic communities."