The paint is peeling off a three-storey grey building in a run-down part of Calcutta teeming with beggars and disabled street children. But busloads of western tourists flock to the spartan house for a guided tour of the new must-see monument in a city rich in colonial history. The visitors usually emerge humbled, often dabbing their eyes, wondering about their own materialistic lives after the face-off.
Mother House - the nondescript Calcutta address where Mother Teresa lived and is buried in a simple grave - is once again under the international spotlight ahead of the 10th anniversary of the death of the Nobel Peace Prize-winning nun.
Missionaries of Charity, the global order founded by the iconic nun, has announced that special prayers will be said and the poorest of the poor fed in Mother House, the order's headquarters, on September 5 to mark what it describes as the 'tenth anniversary of Mother Teresa's going home to God'.
Mass will also be held and special tributes paid to the 'Saint of the Gutters', in the Vatican, the US and many other countries, according to Sister Nirmala, who succeeded Mother Teresa as superior-general of the humanitarian mission six months before her death.
Sister Nirmala also said that a book containing Mother Teresa's unpublished letters and notes is being prepared for release on September 4, a day before the anniversary. Apparently, some of the correspondence was preserved against Mother Teresa's wishes - she had requested that they be destroyed but was overruled by her church. The book highlights a crisis of faith suffered by Mother Teresa for much of her life.
Entitled Mother Teresa: Come Be My Light, the 416-page book has been compiled by Father Brian Kolodiejchuk, a Canadian priest who was one of Mother Teresa's closest confidants and spiritual associate for two decades.
An excerpt from the book quotes Mother Teresa saying: 'If I ever become a saint - I will surely be one of 'darkness'. I will continually be absent from Heaven to light up the lives of those in darkness on earth.'
Significantly, Mother Teresa, who died at the age of 87, is not yet a canonised saint. She was beatified by former pope John Paul II in 2003 on the basis of a miracle she is believed to have performed by 'curing' a 30-year-old Indian woman of stomach cancer. Beatification allows public veneration of the person and for them to be known as 'Blessed'.
However, for sainthood the Vatican requires proof of at least two miracles. Although the Vatican put her on a fast track for possible sainthood, technically she is still a saint-in-waiting.
Nevertheless, she has been called 'a living saint' for decades for espousing the cause of the poor.
Although she was particularly involved with Calcutta, a byword for destitution and urban squalor and the place where she established her first shelters, her agenda gradually included the under-privileged and unwanted in all corners of the world.
She came to India from Yugoslavia in 1929 at the age of 18, started teaching and took her vows as a nun in 1937. Then in 1948, she became an Indian citizen and began working in Calcutta's slums. The charitable Catholic order she founded in 1949 was approved by the Vatican within a year.
In 1970, journalist Malcolm Muggeridge chronicled her work in a film called Something Beautiful for God that brought her to the attention of the west.
Nine years later, she accepted the Nobel Peace Prize on behalf of 'the throwaway of society', but sent the Nobel committee into a tizz by suggesting the gala dinner be cancelled and the proceeds sent to Calcutta's poor. As her fame grew, heads of states and captains of industry courted her and basked in the glory of their association with the Nobel laureate who perfected the art of milking them for donations.
Navin Chawla, a senior Indian civil servant and one of Mother Teresa's biographers, says he was apprehensive that the order would languish after her death.
'I feared donations would dwindle and the flow of novices would ebb, forcing the order to downsize its operations. But happily I was proved wrong,' said Mr Chawla.
'Today, I don't think the legacy of Mother Teresa will recede. I have no doubt her work will proceed as smoothly in the future as it has since 1997 because she trained them to do it so well.'
In 1997, the order ran 600 homes in 126 countries for the outcasts of society, including drug addicts and Aids victims.
Since then, 157 new homes have been opened, taking the tally to 757 homes in 134 countries, according to Sunita Kumar, a businesswoman-cum-socialite-turned spokeswoman for the order.
'It's a tribute to Mother and the good work the sisters are still putting in,' she said. 'Moreover, many big donors, individuals as well as corporate representatives, call up Sister Nirmala regularly to assure her that they will be always there.'
According to one analyst, like other Catholic orders, the Missionaries of Charity reveals little about how much it receives each year in cash and in-kind donations, but it totals millions of dollars.
Most contributions are collected by lay volunteers and channelled into the order's local or regional operations.
The number of foreign volunteers, or young men and women from countries around the world working at 19 MOC-run Calcutta facilities, ranging from orphanages to homes for the dying and shelters for lepers and the mentally ill, has also risen dramatically. 'The flow of volunteers has practically doubled in a decade. About 150 are enrolling every month,' said Ms Kumar.
Mother Teresa once described them as 'beautiful people with a beautiful spirit who make many sacrifices to provide tender love and care'. No doubt, she was the magnet who pulled them to Calcutta, and many thought that they would vanish after her death.
In the past few years, helpers from Japan have outnumbered volunteers from countries such as South Korea, the US, Britain, Germany, Australia, Italy, Spain and South Africa.
Both Ms Kumar and Mr Chawla say that Sister Nirmala, a high-caste educated Hindu who embraced Christianity, has proved to be a worthy successor although she is not as outgoing or tough as her mentor.
'She has been a great successor. She has maintained the momentum and marched ahead on the path shown by Mother Teresa. There are no changes in the system and everyone is still smiling,' said Ms Kumar.
Mr Chawla, who says he has watched Sister Nirmala grow in stature since her elevation, believes that 'the order is in good hands'.
The saga of Mother Teresa has seeped into Calcutta's consciousness. Paying tribute to her, a leading lawyer said: 'We are all Hindus - we believe in God, and we always worship the mother, in the sense of the lady God in our life.
'Today many Hindus worship Mother Teresa as a goddess who renders help. She has joined the pantheon of Hindu goddesses like Kali, Durga and Saraswati who Hindus turn to in their hour of need.'
While most Calcutta residents acknowledge her contribution to society, they criticise the importance attached by the Vatican to miracles in Mother Teresa's beatification and impending sainthood.
Attacking Mother Teresa's alleged 'cure' of a woman's stomach cancer, Prabir Ghosh of the Calcutta-based Rationalist Society of India, said: 'We humbly request the Pope not to make up and spread stories of miracles.
'This may help the Vatican spread Christianity but will do immense harm to the uneducated masses of our country. It's a crime to send the wrong message to them, that modern medicine is ineffective and it is possible to cure illness through medallions, talismans and herbs and threads tied to their arms and legs.'
The order has also been criticised for tying ankles of disabled children to their cots and restraining them while being fed in the Daya Dan home in Calcutta.
After the practice was exposed by a British documentary in 2005, the order promised to improve the quality of care in Daya Dan but the charity is still dogged by reports of inhumane practices.
Aroup Chatterjee, a London-based Calcutta-born doctor, says that 'if Daya Dan were any other care home in India, the authorities would have closed it but the Indian government is in thrall of the legacy of Mother Teresa and is terrified of her reputation and status'.
The documentary also quoted a former MOC senior nun, Susan Shields, who said that one year there was about US$50 million in the bank account held by the New York office alone but the money sat in banks while workers in the homes had to reuse blunt needles for injections.
The order's reputation was also tarnished in 2000 when a nun belonging to the Missionaries of Charity's Mahatma Gandhi Welfare Centre in Calcutta was prosecuted and found guilty of burning a seven-year-old girl with a hot knife.
Mr Chawla, however, shrugs off what he calls 'hit-and-run attacks'. He says Mother Teresa's nuns have their work cut out as long as 'human beings and dogs hunt for food in garbage vats in Calcutta, destitutes shiver in cardboard shelters under London's Waterloo Bridge and Aids victims have nobody to turn to in San Francisco'.