In the case of this building in Drumoyne Drive, Govan, the clue is just above the main door.
A relief carved into the stone depicts a mother holding in her arms a newly-born child.
It was - as any passer-by might guess - a hospital intended as a maternity unit and is a testament to the legacy of one of Glasgow's greatest women.
Isabella Elder had such a high profile around a century ago that she is one of only three women with a statue in her memory in Glasgow.
Her husband was John Elder, one of the city's foremost shipbuilders. Unfortunately he died at the age of 45 leaving Isabella a childless widow.
For the rest of her life she ran her husband's vast shipbuilding interests and became a renowned philanthropist.
She was passionate about health care especially in Govan, then a separate burgh from Glasgow and where her husband had made his fortune.
At the age of 74 the building in Drumoyne Drive became one of the tireless Mrs Elder's projects.
She had it built and equipped and it became Elder Cottage Hospital. The two wards were named Florence Nightingale and Sophia Jex-Blake, two of her nursing contemporaries.
Although it was originally intended to be a maternity hospital, the building became a general hospital.
Mrs Elder funded it until her death in 1905 and it was closed in 1987.