Prince Philip is the oldest member of the royal family, at 97 years old.
Despite officially retiring from royal duties in August 2017, he still loves to live a full and active life.
But even someone as determined and independent as the Duke of Edinburgh can't fight his age.
He's had a few health scares recently, including a scary car crash near Sandringham on January 18th this year.
Here's a look at his rocky health history.
The Duke is famously keen on driving and has been in a road accident at least once before.
In 2010, he injured his ankle when his horse-drawn carriage hit a tree stump on the Windsor Estate. A woman who was in the carriage went to hospital with an elbow injury.
"It was a minor injury and he didn't even go to hospital. He is fine," a Buckingham Palace spokeswoman said at the time.
The Queen's husband loves carriage racing and used to compete in the sport. But these days, it's just a hobby.
In 2004, the Duke spoke of his love for carriage racing in his book, 30 Years On and Off The Box Seat.
"I am getting old," he said. "My reactions are getting slower and my memory is unreliable. But, I have not lost the sheer pleasure of driving a team through the British countryside."
He added: "I have been fortunate to have had a longer innings than most, and I have no intention of giving up while I have a team of willing ponies and dedicated grooms."
Prince Philip was hospitalised twice with a bladder infection in June 2012, which saw him miss out on The Queen's Diamond Jubilee celebrations.
Then aged 91, doctors confirmed the Duke was suffering from a recurring bladder infection.
A Buckingham Palace spokesman said the Duke was taken to hospital as a "precautionary measure" and was expected to stay in hospital for "the next few days".
"The Duke of Edinburgh has had a recurrence of the bladder infection that he had in the summer and has been admitted to hospital for investigation and treatment," a statement from the Palace said.
It was the third time in eight months Philip had been hospitalised. He spent five nights in hospital in June and four nights in Christmas 2011 after heart surgery to clear a blocked coronary artery.
This string of health incidents led to calls for the Duke to slow down. He was one of the hardest-working members of the royal family, undertaking 350 engagements a year.
In 2017 he finally retired from official public appearances.
Prince Philip, then 96, was hospitalised again in June 2017 due to a "pre-existing condition".
"The Duke Of Edinburg was admitted to hospital in London last night, as a precautionary measure, for treatment of an infection arising from a pre-existing condition," Buckingham Palace said in a statement.
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In April last year, a 96-year-old Prince Philip had a successful hip replacement procedure.
"The Duke of Edinburgh has undergone a successful hip replacement operation," Buckingham Palace said in a statement at the time.
"He is progressing satisfactorily at this early stage. His Royal Highness is likely to remain in hospital for several days. He is comfortable and in good spirits."
"The Duke will continue his recovery at Windsor," the Palace said. "His Royal Highness would like to convey his appreciation for the messages of good wishes he has received."
Just a month after the surgery, he was spotted driving himself around in his Land Rover in Windsor.
Prince Philip managed to make it to both Prince Harry and Duchess Meghan's wedding in May, as well as Princess Eugenie's wedding in October.
The last time he was seen at a public engagement was Prince Charles' 70th birthday celebrations in November.
He skipped the royal family's traditional Christmas Day church service at Sandringham Estate, in Norfolk.
The Duke narrowly escaped injury after being involved in a dramatic car crash with another vehicle.
The 97-year-old was pulling out of a driveway onto a freeway in Norfolk, close to The Queen's Sandringham Estate, when his Land Rover collided with another car.
"The Duke of Edinburgh was involved in a road traffic accident with another vehicle this afternoon. The Duke was not injured," a Buckingham Palace spokesperson said in a statement.
"The accident took place close to the Sandringham Estate. Local police attended the scene," the spokesperson said.
Eyewitnesses said they helped extract the Duke from his car and he was conscious but "very, very shocked and shaken."
Two people in the other car involved in the crash were treated for minor injuries.
Apart from being a little rattled, the Duke is in good health. He was seen to by a doctor as a precaution and is now back at Sandringham, without any injuries.