William and Kate are entering a once-isolated land.
Tourists could only visit from the 1970s; TV was introduced in the 1990s; and this former absolute monarchy became a constitutional one with an elected government in 2008.
Bhutan is a Buddhist country with an emphasis on gross national happiness rather than its gross domestic product.
However, the country's prime minister has acknowledged that this much-lauded concept can be overused, and can mask the kingdom's problems with debt, unemployment and poverty.
For two days the Cambridges will be guests of a young king and queen that are held in high regard by its subjects.
They'll learn how Bhutan - which once revelled in its remoteness - is now facing the challenge of how to retain its Buddhist traditions while also embracing the modern world.

The Spaniard, 23, started on pole but slipped to fifth place after an early technical issue.
He recovered and overtook Valentino Rossi with 12 laps to go, securing his fourth win of the season and taking his championship total to 248 points.
Rossi struggled to close down Marquez's lead and fell behind defending champion Jorge Lorenzo to finish in third.
Victory - the 28th of his career in the top category - gives Marquez a clear lead over second-placed Rossi, with four races remaining.
Earlier, Brad Binder became the first South African motorcycle grand prix world champion since 1980 as he won the Moto3 title.
1. Marc Marquez (Spa) Honda - 41 minutes 57.678 seconds
2.  Jorge Lorenzo (Spa) Yamaha - 42:00.418
3.  Valentino Rossi (Ita) Yamaha - 42:03.661
4.  Maverick Vinales (Spa) Suzuki  - 42:05.916
5.  Cal Crutchlow (GB) Honda - 42:10.899
6.  Dani Pedrosa (Spa) Honda - 42:14.750
7.  Aleix Espargaro (Spa) Suzuki - 42:16.200
8.  Pol Espargaro (Spa) Yamaha - 42:17.110
9.  Alvaro Bautista (Spa) Aprilia - 42:20.749
10. Stefan Bradl (Ger) Aprilia - 42:25.576
1. Marc Marquez (Spa) Honda - 248 points
2. Valentino Rossi (Ita) Yamaha - 196
3. Jorge Lorenzo (Spa) Yamaha - 182
4. Dani Pedrosa (Spa) Honda - 155
5. Maverick Vinales (Spa) Suzuki - 149
6. Cal Crutchlow (GB) Honda - 105
7. Andrea Dovizioso (Ita) Ducati - 104
8. Andrea Iannone (Ita) Ducati - 96
8. Pol Espargaro (Spa) Yamaha - 96
10. Hector Barbera (Spa) Ducati - 84

The incident occurred on Great Northern Road near to its junction with Clifton Road at about 12:00 on Saturday.
Police Scotland has appealed for witnesses to the crash.
Police said the collision involved a black Yamaha motorcycle, a black Vauxhall Adam and a silver Volkswagen Caravelle.
Sgt Malcolm Kinross, of Police Scotland's divisional road policing unit, said: "Our thoughts at this difficult time are with the family and friends of Damian Piotrowski.
"We continue to investigate the circumstances of this collision and we are appealing for anyone who was in the area at the time to come forward.
"In particular, we are keen to speak to passing motorists in a white Vauxhall Insignia and a dark coloured Nissan Qashqai who may have witnessed the collision."
The descent into Paro by plane, which has to navigate a mountainside, is not for the faint-hearted.
[NEXT_CONCEPT]
MotoGP championship leader Marc Marquez moved 52 points clear in the title race with victory at the Aragon Grand Prix.
[NEXT_CONCEPT]
A 27-year-old motorcyclist who died following a three-vehicle crash in Aberdeen has been named by police as Damian Piotrowski.