Saint Nicholas Church, Ghent

Stand still for a moment and look at the stone. It is not the warm, honey-coloured stone you might expect from a medieval church. It is cool, blue-grey, almost the colour of a winter sky over the North Sea. Run your eyes up the walls and the shade shifts with the light: slate in shadow, silver where the sun touches it. Around you, trams rattle past, bicycle bells ring, and the smell of coffee and fried food drifts from the cafés of the Korenmarkt. This is Saint Nicholas Church.

The church sits at the heart of old Ghent, right beside the Korenmarkt, the old Corn Market. For centuries this square was where grain arrived by water and changed hands. Ghent grew rich on trade, first in grain and then in cloth. The merchants who made that money wanted a church that matched their status. So it makes sense that this church carries the name of Saint Nicholas. He is the patron saint of merchants, sailors and travellers. He is also, of course, the saint behind the Christmas figure children know today.

The building you see replaced an earlier Romanesque church. Romanesque is the heavy, round-arched style of building that came before Gothic in Europe. Work on the Gothic church began in the early thirteenth century, and building went on in stages over a long time. That is normal for a medieval church. Generations of masons worked here. Many of them never saw the finished result. Each one added a piece to a project that was larger than a single lifetime.

Here is the first detail most visitors miss. That blue-grey stone did not come from Ghent. It came from the area around Tournai, a city in what is now southern Belgium. Blocks were carried north by boat along the Scheldt River. The Scheldt is the great river of this region, and it connects Ghent to the sea. The stone gave its name to a whole style of building. Historians call it Scheldt Gothic, after the river that carried both the stone and the ideas.

Scheldt Gothic has a few clear signs, and this church shows them well. Look for the slender round turrets at the corners of the building. They rise like thin towers and give the church a sharp, upright outline. Then look at the main tower. It does not stand at the front, above the entrance, as in many Gothic churches. It rises from the centre, over the crossing, where the long nave meets the arms of the church.

That central tower is the second surprise. It works as a lantern tower. From the inside, it is open above the crossing, and windows high in the tower let daylight fall down into the church. For the builders, this was a practical choice as well as a beautiful one. Ghent's streets were tight and the city was crowded. A tall tower over the middle of the church could be seen from far away, and it pulled light into the centre of the building.

Now turn and look along the skyline. Ghent is famous for a row of three towers that stand almost in a line. The first is this one, Saint Nicholas. The second is the Belfry, the civic tower that once held the town's charters and its bells. The third is Saint Bavo's Cathedral. Church, city, cathedral. Together they show the three powers of medieval Ghent: the merchants, the town government, and the bishop's church.

The best place to see all three together is the Saint Michael's Bridge, a short walk away over the river Leie. From the middle of the bridge, the towers line up one after another. It is one of the classic views of Flanders. Take a few minutes there. Notice how each tower has its own character. The church tower is solid and grey. The Belfry is taller and more decorated. The cathedral tower rises in the distance, heavy and square.

Step inside, and the noise of the square drops away almost at once. The air is cooler. Your footsteps sound louder on the stone floor. The interior is tall and open, and the same grey stone carries the long lines of the columns up toward the vaults. Look up at the crossing, under the tower, and you will see how the light from above changes through the day. On a bright morning it falls in pale bands across the floor.

The church holds a notable organ built by Aristide Cavaillé-Coll. He was a French organ builder of the nineteenth century, and his instruments are known around the world for their rich, orchestral sound. Organists still travel to play his instruments. If you are lucky enough to arrive during a concert or a rehearsal, stay for a while. The sound fills the stone space and seems to come from every direction at once.

Like many old churches in Europe, this one has had difficult periods. Over the centuries it suffered damage, neglect and years of decay. By the twentieth century the stone needed serious care. A long restoration followed, and it continued for decades. Much of the clean, crisp stone you see today is the result of that patient work. Look closely and you can sometimes see the difference between older, darker blocks and newer, paler repairs.

Think about the people who have stood where you are standing. Grain merchants checking prices in the market. Sailors giving thanks for a safe return. Guild members gathering for their own chapels and celebrations. Families bringing children to be baptised. The Korenmarkt outside has changed many times. The trade has moved elsewhere, and cafés now fill the space where grain was once sold. But the church has stayed in the same place, with the same grey stone, through all of it.

Before you leave, walk once slowly around the outside of the building. Touch the stone if you can reach it. Feel how cool and smooth it is under your hand. Look up at the corner turrets again, and then at the central tower against the sky. Listen to the trams, the bicycles and the voices in the square. As you walk toward the river, turn back once more. The grey tower will still be there, rising over the rooftops, as it has for centuries.