What's in a name?
Rather than being named after a king or something equally as grand, the park's moniker comes from a leper hospital which stands roughly where St James's Palace is today. The hospital was named after James the Less, and housed female lepers who used the area — now the park — to raise hogs and other animals.
The disappearing lake
Today the lake is one of the park's most prominent features, but for six years last century, it didn't exist.
The lake was drained in 1916 to allow temporary government buildings to be built there in the first world war. Ministry of Shipping buildings appeared on the lake bed and remained there until the lake was filled with water again in 1922.
Deer breeding
Henry VIII was known for his love of hunting; he regularly used Regent's Park as a hunting ground. St James's Park wasn't quite big enough for his needs, so he put it to use as an area for breeding young deer — once they were old enough, they were shipped off to Hyde Park and Regent's Park to face their fate.
The pelicans
Most people are familiar with St James's Park's best known residents, the pelicans. But where did they come from?
The birds were donated to King Charles II by a Russian ambassador in a visit in 1664 — because really, what else do you give the king who has everything? Today's pelicans are the descendants of the original arrivals.
The royal stalker's skeleton
As recently as 2011, a skeleton was found in St James's Park, believed to have been there for around three years before its discovery. It was found on West Island, one of the islands on the lake, out of bounds to the public.
It turned be the corpse of Robert James Moore, an American who had moved to the UK in 2007, and who was obsessed with the Queen. It's thought that he set up camp on the island as it's just 100 yards away from the front of Buckingham Palace.
King Charles I's final walk
King Charles I took his final stroll through the area of St James's Park on 30 January 1649 — the day of his execution. His route ended at Banqueting Hall on Whitehall, where his execution took place.
Duck Island Cottage
Ever stumbled across this cute-as-a-button building on the edge of the lake and wondered what it is? It's Duck Island Cottage, and was built by the Ornithological Society of London, in 1837. That same year, the Society donated some birds to the park.
The cottage is Grade II listed, while the rest of the island it sits on is home to the water treatment facilities and pump for the fountain in the middle of the lake.
Exotic history
James I made several changed to the park on his ascension to the throne — mainly to cater for the exotic menagerie he wanted. He had the park, which sat on marshland, drained and landscaped, and moved camels, crocodiles and elephants in.
Birdcage Walk
Birdcage Walk is the road which runs along the entire southern side of the park. It's so named because King James I had a particular penchant for exotic birds, and kept many of them in cages and aviaries lining this street. The birds continued to reside here into the reign of King Charles II, although it's worth pointing out that Birdcage Walk was a private road until 1828, only open to the royal family and the Duke of St Albans.
The short-lived pagoda
The bridge which crosses the lake in the park is today known as The Blue Bridge. Its predecessor was a lot more ornate, and was built in 1814 to celebrate the end of the war with France. A sizeable Chinese pagoda was built in the middle of the park at the same time.
The celebrations involved fireworks in the park... which set fire to the pagoda and burnt it down, killing one person and injuring others in the process.
The ornamental bridge only lasted until 1825, and has since been replaced with the bridge that's still there today.
Storey's Gate
To the south east of the park is a road called Storey's Gate. It's named after Edward Storey, once the keeper of the birds on Birdcage Walk, and the road was originally one of the main entrances to the park, along with Buckingham Gate in the south-west corner.
Goodbye trees
Like all of the Royal Parks, St James's Park used to be a lot more tree-heavy. During the austerity of Cromwell's rule, many local people chopped the trees down to used them for fuel. Nice one, Ollie.