As part of a series of articles BBC News Online reporter Jane Elliott looks behind the scenes of the NHS.
This week we focus on how a leading heart hospital has lasting ties with Australia and New Zealand.
Mention Harefield Hospital and most people think immediately of eminent cardiac transplant surgeon Magdi Yacoub.
But what many do not realise is that the hospital has been in existence since the start of World War I.
Harefield has strong links with Australia and New Zealand, and was in fact set up to provide medical help for the wounded ANZAC (Australia and New Zealand Army Corps) soldiers.
It also has the largest ANZAC cemetery outside Australia and New Zealand.
Even now ANZAC day is marked each year with a service at St Mary's Church, which is attended by the Australian and New Zealand High Commissions.
A centre in the hospital has been dedicated to the brave men who were treated there and their pictures adorn the walls.
When the hospital was first set up at the end of 1914, it was intended to take only 150 patients, with just a handful of nurses.
But planners had vastly underestimated the need, and within a fortnight of opening, Ethel Gray - the Queen Alexandra nurse in charge of the unit - was told to prepare for 1,000 more arrivals.
Wounded patients dressed in Australian uniform soon became a common sight in the village.
The hospital became a place of renown and in August 1915 even received a visit from King George V and Queen Mary, who quizzed patients about the battle of Gallipoli.
Many described colleagues dying in their arms or being shot down beside them.
By May 1916 the hospital had admitted over 1,500 men.
With a vast range of injuries to deal with, it soon became a specialist centre for radiography, electrotherapeutic services, massage and physiotherapy, ear, nose and throat surgery, and for patients suffering from breakdowns.
Patients often brought mascots from home. One soldier had a cockatoo brought from the trenches of Gallipoli, which had the unfortunate habit of imitating the screech of Turkish shells.
Another brought a wallaby, which they presented to one of the volunteer workers.
Unfortunately it was later shot by a local farmer who had no idea what it was.
The hospital closed its doors to the ANZACs as the last left in January 1919. The remaining 691 patients were discharged and the treatment centre closed.
But Cheryl Thompson, of Harefield Hospital, said the ANZAC connection remained important.
"It is our history. Perhaps without the ANZACs there would not be a hospital on this site today.
"It is important to remember those that fought to save our country, and when you look at the old photographs, which have been reproduced and hung in the ANZAC centre, there is a real sense of connection to our past, you can step back in time.
"Each year on ANZAC day - April 25th, a service is held at St Margaret's church, where the ANZAC graves are located. This service commemorates those Australian and New Zealand soldiers who lost their lives fighting in a war, thousands of miles from their homes."
Harefield later became a refuge for tuberculosis patients and in 1921 opened its doors to the first patients as the Harefield Sanatorium.
Now world renowned, the Harefield hospital is under threat, with plans to relocate the Middlesex heart and lung transplant hospital announced on 8 October last year.
The hospital's care services are due to be relocated to a new £360m health complex in Paddington, which could bring to an end to almost a century of health care.