While riding a train to Darjeeling, India, Sister Teresa Bojaxhiu, later Mother Teresa (pictured), experienced what she later described as the "call within the call", directing her to "leave the convent and help the poor while living among them".

Darjeeling is a city in the northernmost region of the Indian state of West Bengal. Located in the Eastern Himalayas, it has an average elevation of 2,045 metres (6,709 ft). To the west of Darjeeling lies the easternmost province of Nepal, to the east the Kingdom of Bhutan, to the north the Indian state of Sikkim, and farther north the Tibet Autonomous Region of China. Bangladesh lies to the south and southeast, and most of the state of West Bengal lies to the south and southwest, connected to the Darjeeling region by a narrow tract. Kangchenjunga, the world's third-highest mountain, rises to the north and is prominently visible on clear days.

Mary Teresa Bojaxhiu, better known as Mother Teresa or Saint Mother Teresa, was an Albanian-Indian Catholic nun, founder of the Missionaries of Charity and is a Catholic saint. Born in Skopje, then part of the Ottoman Empire, she was raised in a devoutly Catholic family. At the age of 18, she moved to Ireland to join the Sisters of Loreto and later to India, where she lived most of her life and carried out her missionary work. On 4 September 2016, she was canonised by the Catholic Church as Saint Teresa of Calcutta. The anniversary of her death, 5 September, is now observed as her feast day.