St Rumbold's Cathedral, Mechelen, Belgium: An opportunity to rummage among the workings of a monumental cathedral

I'm always looking up in cathedrals. I stand on the floor and crane my neck at arches and stained glass and flying cupids, all designed to make me feel like an unworthy ant in the house of almighty God. Not in Belgium's historic town of Mechelen, though. In Mechelen, I look down through a great hole in the ceiling at the nave and the tops of organ pipes. I've never seen a cathedral from this angle. It's disorienting. I feel somewhat dizzy, as if I'm going to tumble down with a splat onto the floor like a fallen angel.

I'm also exhilarated. Somehow this building doesn't seem like a celebration of God, but rather of humble people and their extraordinary endeavours. The organ pipes are the size of tree trunks. Above my head, an alarming crosshatch of timbers is all that holds up the tower.

Tradesmen once walked like hamsters inside a huge wooden wheel, now encased in cobwebs, that made pulleys turn and hauled up building materials. The tower was built above the heads of these medieval workers, showing quite the faith in God and their own engineering.

So far, I'm just 160 steps up. It's another 72 steps to the forge chamber where the tower's bells and metalwork were once repaired. The steps are polished to a black shine with age and wind ever onwards. The architectural style evolves into a more elaborate High Gothic, and there are more and bigger windows. I can hear pigeons cooing. You can sometimes see one of the falcons that prey on them, using the tower for hunting as they would a cliff face.

Normally I don't bother much with climbing old towers. You have to contort your way past perspiring tourists and shrieking teenagers, and all you ever see are spiders' webs and rooftop views. Mechelen is different, however. There are ridiculously few tourists in this lovely old town, even though it has 300 listed buildings and is a seven-minute train ride from Brussels airport. And in the tower of St Rumbold's, you can stop off at any of seven floors on the way for a behind-the-scenes stickybeak.

I find the bells 400 steps up. Don't ask me how they got here. The smallest weighs 16 kilograms but the biggest is eight tonnes. Two whole carillons of bells hang from gigantic rafters. These days they're played automatically, but sometimes a carillon player heaves his way upwards and operates the wooden keyboard to set the bells donging and the tower vibrating with the noise.

Wedged on the floor above is the mechanism of the tower's 18th century clock. Here too I can clamber around on wooden walkways for an up-close look. You don't climb this tower for the views but for the remarkable opportunity to rummage among the workings of a great cathedral.

There are views, though. When I reach the last of 538 steps I pop out on a 21st century skywalk in glass and metal. No squinting through tiny apertures or safety mesh on this tower. There's no shelter from rain squalls and nothing stands between me and views clear across Flanders. I can see the spires of Antwerp and Brussels, both 30 kilometres away. Straight down below me is Mechelen's town square, the wonderful Grote Markt. Its gable buildings sprout golden roosters and eyebrows of petunias.