The palace's alleys and arches are a glittering tapestry woven from more than 1,000 years of Prague's rich history.
"There is so much in one place. It's huge. I think people don't even know that you're still in the castle," said American tour guide Natalia Lucak.
It can take an hour to cross the castle's grounds if you're walking briskly, but you wouldn't have the time to appreciate the 4,000 paintings that decorate the grounds
The King's Castle wasn't always so grand, though.
"This castle had very humble beginnings as, essentially, an earthen mound," said Eric Jager, of UCLA. "Then it develops into what we have today, which is this huge, magnificent castle on the hill."
The bigger the castle got, the richer the intrigue.
For more than 1,000 years the castle, sat perched high above the city, has been been steeped in legends and symbolism.
In 1939 Adolf Hitler came to the grounds to let everyone know he'd taken Prague. And it also was at the castle that the citizens held vigil and finally wept with joy when communism melted away.
Even today its medieval secrets still tantalize.
To even get to the real jewels requires using seven different keys from seven people, including the president and prime minister who must get together to open the door.
The castle also has a chapel that holds the remains of Good King Wenceslas, whose brother had him murdered on the way to Mass in the year 935.
History literally can get steep inside the castle's walls.
Take Prague's most notorious window where in 1618 a band of Protestant noblemen stormed the castle, grabbed three of the king's men and chucked them out of the window.
They survived the 50-foot fall because they landed in a pile of manure. Still the events set off the 30-year war and window hurling became the Prague trademark method for dealing with political enemies.
The Prince From Boston
Part of the castle belongs to a Bostonian named William Lobkowicz. Lobkowicz's ancestors lived in the Prague Castle for generations until his grandparents lost everything to the Nazis and the communists.
"Our ancestors were collecting really the finest things throughout the 700 years of our family history," Lobkowicz said.
Today, part of the castle, the only part that is privately owned, is back in the family.
"It was really the call of the roots," Lobkowicz said. "We had four lawyers working full time for seven years just to see, find the properties, find the papers to see if we could in fact get some of these things back."
Lobkowicz turned his family's part of the castle into one of Prague's most popular museums.
There, he could be called Prince William, but Lobkowicz said the title makes him uncomfortable.
"Titles were abolished in 1918, so we're just ordinary citizens today. But we live in our history, of course, with our museum."