Back to our search for the river where birthday celebrations to honor Thailand's king are underway this week. The answer to today's Geo Quiz is the Chao Phraya River.

Chao Phraya River: photo Adam Carr

Its name means river of kings, and it snakes its way through the center of Bangkok.

Now, as for that craze for pink we mentioned earlier.

You see, Thailand's King Bhumibol turns 80 years old tomorrow...and he was recently hospitalized. The BBC's Jonathan Head in Bangkok says the king recovered...with a fashion statement.

“When he emerged from hospital he decided to wear a brightly colored pink blazer, he's fond of colored blazers and immediately a lot of astrologers in Thailand started to say this is the color you have to wear to give the King good luck and to extend his life and the whole country has taken it up.”

King Bhumibol

And that's why Thais are donning pink.

“It's something where people feel they almost got to do it, you stand out if you don't wear one of these shirts especially if you work in a big company or the government, and it's a national expression of feelings for the king. It's very moving to see there's also something slightly disturbing about it is all very North Korean.”

But one Thai woman we spoke with said the affection her compatriots feel for their king is genuine.

“Everybody we wish that he will have a long life very good health, for 10 years I wish, so today I wear pink!”

So it's pink for good health. But tomorrow, Thais will wear the King's traditional birthday color...yellow. Even the BBC's Jonathan Head may add a touch of yellow to his attire.

“I might possibly wear a yellow tie but I need to be able to stand out to try and find my colleague among what's expected to be possibly hundreds of thousands of people out on the streets around the palace tomorrow.”

The Royal birthday bash gets underway tomorrow along Thailand's Chao Phraya River...the answer to today's Geo Quiz.

By the way, another fun fact the King of Thailand was born 80 years ago in Cambridge Massachusetts