Saint Joseph's Cathedral, Hanoi

Stand still for a moment in the small square and listen. Motorbikes hum past on every side, a vendor calls out from a cart, and somewhere a glass clinks against ice. Then you look up. Two grey bell towers rise above the rooftops, their stone darkened and streaked by more than a century of tropical rain. In the warm, damp air of Hanoi, this church looks like it came from a much colder place. In a sense, it did.

This is Saint Joseph's Cathedral, the oldest church in Hanoi and the heart of the city's Catholic community. Locals often call it simply Nha Tho Lon, which means the Big Church. The name of the street at its feet, Nha Tho, means Church Street. The building is so central to this neighbourhood that the streets around it took their names from it.

The cathedral opened at Christmas in 1886, after roughly two years of construction. Vietnam was then coming under French colonial rule, and the French Catholic mission wanted a grand cathedral at the centre of Hanoi. The project was led by the French bishop Paul-François Puginier. The style is Neo-Gothic, which means a nineteenth-century revival of the pointed arches and tall towers of medieval European churches. Many visitors notice the resemblance at once. The square twin towers and the broad front were inspired by Notre-Dame de Paris.

Here is something many visitors miss. The ground under your feet was sacred long before any church stood here. For centuries this site held the Bao Thien Pagoda, a Buddhist temple with a tall tower. The tower dated back to the Ly dynasty, the royal family that ruled Vietnam from the eleventh century and moved the capital to this city. The tower had fallen into ruin long before the French arrived. Then the pagoda was cleared, and the cathedral was built on the site. So one place of worship stands on the memory of another.

The money for construction also has an unusual story. According to historical accounts, part of the funding came from public lotteries organised in the colony. It is a surprising thought. Some of the cost of this solemn stone church was paid by people buying lottery tickets and hoping for luck.

Now look closely at the facade. The walls were built from brick and covered with a render, a layer of plaster made to look like stone. Over the decades, heat, monsoon rain and city traffic have turned the surface a mottled grey and black. Some people find it gloomy. Many others love it. The weathering makes the building look much older than it is, and it softens the hard lines of the Gothic design.

Above the main doors, find the large round rose window, a circle of stained glass in the centre of the front. On either side, the towers rise in clean, square shapes and carry the bells. Between them, the pointed arches lead the eye upward. This is the central idea of Gothic architecture. Everything pulls you toward the sky. Even the busy square below seems to shrink when you stand close and tilt your head back.

If the doors are open, step inside quietly. The light changes at once. The street glare gives way to a cool, dim interior, and coloured light falls through the stained-glass windows. The windows were made in the European tradition, and they show saints and scenes from the Bible. A long nave runs toward the altar. A nave is the main central hall of a church, where the congregation sits. The ribbed vaults above are painted, and the high altar shines with gilded wood.

Inside, keep your voice low. This is not a museum. It is a working parish church, and people come here to pray at all hours. You may see an elderly woman with her head bowed, a young couple lighting a candle, or a family on a weekday afternoon. Mass is said in Vietnamese, and on a full Sunday the singing fills the whole hall. Even if you do not understand the words, the sound of hundreds of voices together stays with you.

The cathedral has lived through every stage of modern Vietnamese history. It saw colonial rule, war, the division of the country and the long years that followed. There were times when religious life here was difficult and quiet. Today the church is full again on feast days. At Christmas the square is packed with people from across the city, Catholics and non-Catholics alike. They come for the lights, the nativity scene and the atmosphere of a big shared celebration.

Now turn around and look at the square itself. This may be the best part of the visit. Along the edges, people sit on tiny plastic stools close to the ground. They are drinking tra chanh, a sweet iced lemon tea that is cheap and refreshing. Many add a bowl of roasted sunflower seeds and crack them while they talk. This lemon-tea culture around the church became so popular with young Hanoians that the drink is often linked with this very spot.

The streets that spread out from the square are worth a slow walk. Small cafes, clothing boutiques and old shophouses line the lanes. A shophouse is a narrow building with a shop on the ground floor and a home above. Hoan Kiem Lake, the green heart of the old city, is only a few minutes away on foot. In a short walk you move from French Gothic stone to Vietnamese street life and back again.

Before you leave, find a stool, order something cold, and look at the towers one more time. Notice how the dark stone sits against the trees and the tangle of electric wires. Notice the motorbikes parked at its feet and the children playing on the steps. This church was built as a symbol of foreign power. Over more than a century, the city slowly made it its own. As you walk away, listen for the bells... and let the sound follow you into the streets of Hanoi.