With its early Christian Byzantine style, Victorian features and imposing tower, Westminster Cathedral has been hailed as one of London's "greatest secrets".
Renovation work at Westminster Cathedral will begin after Easter
The foundation stone for the "mother church" of the Roman Catholic community in England and Wales was laid in 1895, but the building was not opened to the public until 1903.
After 113 years, three of the church's four domes and the arches supporting them are showing signs of age.
A structural survey conducted last year found the Grade I listed building needed to undergo extensive renovation to be safe for worshippers.
Brickwork on the domes has deteriorated so much that there is a real danger debris could fall on to the floor.
The Catholic Archbishop of Westminster, Cardinal Cormac Murphy-O'Connor, has therefore made an appeal for donations to meet the repair cost of £3m.
'Hitchcock's Requiem Mass '
The 2,000-seat cathedral in Victoria, central London, was designed by architect John Francis Bentley.
Its striped brick, marble exterior and continental style piazza makes it stand out from other churches.
About 4,000 worshippers attend the Mass on Sundays.
The unique building and its bell tower was featured in Alfred Hitchcock's 1940 film Foreign Correspondent.
About 4,000 attend the Sunday Mass in the cathedral
Forty years later, shortly before his death, the director requested his Requiem Mass to be held at the cathedral.
The church's location and design has led to its comparison with the Dr Who's Tardis.
The cathedral's administrator Monsignor Mark Langham said: "It is amazing, the number of people who have not been in it and do not realise it is there," he said.
"When they walk in, it is a bit like the Tardis really, it is so much bigger on the inside than they realise. It deserves to be better known."
In 1982, the cathedral hosted the first Mass celebrated by Pope John Paul II during his tour of the nation.
Composer Sir Edward Elgar conducted the first performance of The Dream of Gerontius in London in the church in 1903, the year it opened for the public.
Renowned visitors include US President John F Kennedy, who attended his niece's baptism in the church in 1961.
In 1995 the Queen marked the centenary of the cathedral's foundation.