London's skyline is constantly changing. Construction cranes pepper the horizon and new skyscrapers shoot up at a dizzying rate. Just as Londoners get used to one unusually-shaped steel and glass tower on the City skyline, another muscles in on the view.

There is the Gherkin, the Walkie Talkie, the Cheesegrater and – coming soon – the tallest of them all: 1 Undershaft but, amid all the change, there seems to be one constant: the 47 churches in the Square Mile, as the City of London is known. Temples of Mammon go up and come down and go up again, but Sir Christopher Wren's places of worship stand their ground.

Reuters photographer Toby Melville loves finding creative ways to capture these historic survivors. He says: "A spire or church tower, once prominent, may now be swallowed up or hidden. But look hard – it's still there down a street or alley, emerging between the glass and steel."

London churches
A city worker walks through a forest of skyscrapers, including the Lloyd's Building and the Gherkin, surrounding St Andrew Undershaft church, constructed in 1532Toby Melville/Reuters
London churches
The spire of St Edmund the King church is dwarfed by 20 Fenchurch Street, known as the Walkie TalkieToby Melville/Reuters
London churches
St Stephen Walbrook, another church rebuilt by Sir Christopher Wren after the Great Fire of London, is seen between an entrance to Bank Station and the City of London Magistrates CourtToby Melville/Reuters
London churches
The tower of St Alban, Wood Street, is hemmed in by office buildings. The church building, which was designed by Sir Christopher Wren after the Great Fire of London, was severely damaged in the Second World War, leaving only the towerToby Melville/Reuters
London churches
St Andrew Undershaft church is surrounded by steel and glass in the CityToby Melville/Reuters
London churches
St Bride's Church is reflected in a City office block window. The church building, designed by Sir Christopher Wren after the Great Fire of London, was rebuilt after the Second World War as it was gutted by bombs dropped on the Blitz night of 29 December 1940Toby Melville/Reuters

In the 16th century, there were 111 churches in the City. Eighty of them were destroyed by the Great Fire of London of 1666, and 51 were rebuilt under the direction of Sir Christopher Wren with backing from King Charles II.

In the Victorian period, congregations shrank as people moved out to London's new suburbs. More than a dozen churches were replaced by buildings devoted to commerce, not worship.

Nearly all of the City's churches were damaged by German bombing during the Second World War and rebuilt to Wren's designs. Only a handful of Wren's masterpieces survived the Blitz, most famously St Paul's Cathedral. Views of the cathedral are protected from various locations around the city, leading architects to come up with creative designs for skyscrapers, such as 122 Leadenhall Street, known as the Cheesegrater because of its wedge shape.

London churches
One of London's most recognisable sights, the dome of St Paul's cathedral, is reflected in a bus window. Rebuilt by Sir Christopher Wren after the original was destroyed in the Great Fire of London, St Paul's was the tallest building in London for more than 300 years, until it was overtaken by the BT Tower in 1962Toby Melville/Reuters
London churches
A reflection of St Paul's Cathedral is seen refracted in raindrops on a metal plaque following heavy rainfall in the City of LondonToby Melville/Reuters
London churches
A City worker on the stairs leading to Millennium Bridge is silhouetted against St Paul's CathedralToby Melville/Reuters
London churches
St Paul's Cathedral is seen at dusk as construction cranes prepare to make more changes to the skyline of the City of LondonToby Melville/Reuters

Developers would love to get their hands on these prime locations. Voluntary organisations fight to keep the City's centres of worship alive today. They try to widen their appeal by staying open all day and offering on-site cafes, lunchtime concerts and recitals to entice City workers, passers-by and tourists.

London churches
The City of London business district is seen in the distance behind church spires at dawnToby Melville/Reuters
London churches
A worker looks at his phone in the remains of St Dustan in the East church. Severely damaged in The Blitz, the ruins were turned into a public garden which opened in 1971Toby Melville/Reuters
London churches
St Margaret Pattens, yet another church rebuilt by Sir Christopher Wren after the Fire, is reflected in the Walkie TalkieToby Melville/Reuters
London churches
St Edmund The King church is reflected in an office building in the City. The former parish church, which was constructed to the designs of Sir Christopher Wren after the Great Fire of London, is no longer used for regular worshipToby Melville/Reuters
London churches
The Shard towers over the spire of St Magnus the Martyr church, rebuilt by Sir Christopher Wren after the Great Fire of LondonToby Melville/Reuters

Melville says: "For some, these buildings provide respite from the bustling life of big business, an antidote to the frenzied pace of modern life. For others, it's a place to eat a sandwich, sit and pause for thought, or enjoy buildings and artefacts from a different era. Amen to that."