By Paul Nassar, NBC News Producer

They come in their tens of thousands, a bedraggled bunch, walking barefoot for weeks to reach the small town of Lalibela. Perched high in the Ethiopian mountains, this former medieval capital is one of the holiest sites for Christians in Ethiopia. It is where King Lalibela -- the monarch after whom the town is named -- decided to build his African Jerusalem.

The churches and monasteries here were not built in the conventional sense. Instead they were carved out of red volcanic rock and their spiritual pull is as strong today as it was when these sites were freed from their surrounding rock more than 800 years ago.

Lalibela has been called the 8th wonder of the world, and it's easy to see why. The scale of the buildings is daunting. The effort needed to build each church and monastery must have taken decades of slow back-breaking work.

The people around me had dropped everything weeks ago to began their long trek to Lalibela. The average Ethiopian Christian undertakes this journey three times on average in their life.

The fortunate ones drive the almost impassable dirt roads to get there. Most, however, complete this pilgrimage on foot, sleeping out in the open with nothing but their rags and bible for comfort. To shield themselves from the biting cold, the pilgrims pick the scented leaves and flowers they find along the way in order to scatter them on the ground and bed down for the night.

Paul Nassar / NBC News

A throng of pilgrims and a few tourists leave one of the church complexes in Lalibela, Ethiopia.

I was in Ethiopia to do some work for a charity named the Ethiopia Education Foundation. I had given myself a few days to see other parts of the country while I was there. When I mentioned my travel plan to friends, their first response was always the same: Why on earth do you want to go there? I have to admit, part of me was skeptical, but mostly, I was curious. What I found in Lalibela did not disappoint.

A secret, for now

In fact, it is amazing to me that this town has been kept such a secret from tourists all these years. The secret, however, seems to be out and increasingly you see the odd tourist here and there among the throng.

Most of the tourists were Europeans. Like me, they had heard of the many wonderful sites in the country and were curious. Many others were Ethiopian Americans, here to discover the lands their ancestors left to make a new life in America.

Unlike so many other tourist sites around the world, however, Lalibela is not a series of ruins from a long forgotten era. It is brimming with life: Its markets over-flowing, and its churches still a place of refuge.

There is no doubting the depth of religious belief held by the pilgrims either. Once they enter one of the churches, many fling themselves in front of the Ethiopian icons that line the walls, or dance outside thanking God for bringing them safely to their destination.

Paul Nassar / NBC News

A young pilgrim in Lalibela, Ethiopia gathers leaves and flowers to sleep on before the sun sets.

The pilgrims spend their days going from one shrine to another. They read their bibles in quiet contemplation. They listen to the preaching of various monks, set apart from the rest of the crowd by their bright yellow clothing. And when the sun finally sets, they stream out to the outskirts of the town, crouch down in groups under a tree, and chant hymns late into the night.

For now, the town belongs to them. As I walk past, I see the new hotels being built all around. It won't be long before these pilgrims will have to cede this town to the armies of tourists traipsing through their once holy sites.