If you have only one day in Bangkok and only time to visit one part of town, it will probably be the city's old town, Rattanakosin, home to some of the most famous and important sites in the city. Among these is Wat Phra Kaew, the Temple of the Emerald Buddha. Located inside Bangkok's Grand Palace Complex, the temple is the location of the Emerald Buddha, and the most sacred and important Buddhist site in the country.
The Grand Palace is located in an area of Bangkok called Rattanakosin, which is the city's old town built along the Chao Phraya River. If you are staying in the backpacker hub Khao San Road and the Democracy Monument area, you will be very close.
The most scenic way to get to the Grand Palace from another part of town is by boat (orange flag public boat or blue flag tourist boat) running along the Chao Phraya River from Central Pier at Saphan Taksin BTS station all the way to the Grand Palace at Tha Chang Pier (Pier Number 9).
Alternately, take bus #12 from Victory Monument.
At 500 baht (approximately $15 per ticket), admission to the Grand Palace complex is quite high for Bangkok standards.
What to Wear:
As not only thee holiest site in the country but also being on royal property, a conservative dress code is strictly enforced. Men and women must wear long pants (women may wear long skirts) and covered shoulders. Neither men nor women may wear sleeveless shirts. No shorts allowed. If you are improperly dressed, you will not be allowed to enter the palace without renting or purchasing overpriced and tacky fisherman pants and t-shirts to cover up, costing you a lot more money.
One of Bangkok's most common scam is that of the "helpful tuk-tuk driver" who will stand outside of the palace informing visitors that the palace is closed today (because today is Sunday, because it's a national holiday, because they are cleaning...), and offering instead to take the visitors on an overpriced ride through the city to their friend's tailor shops. This is never true. The palace is open daily. Smile politely and ignore this advice, and proceed to the entrance.
What to See:
The complex is massive, and it's hard to see everything in one visit. When visiting, be sure to see the Emerald Buddha and the Grand Palace, which is still an operational ceremonial palace managed by the Royal Household Bureau.
The Grand Palace
The lower stories of the palace are quite reminiscent of a European palace, but the roofs and eaves are distinctively Thai, with golden spires and elegant terraced roofs. Constructed in 1782 by King Rama1 I, the first king of the reigning Chakri Dynasty, the Grand Palace is the center of Thai royal authority.
The Grand Palace was the official full-time royal residence of the first eight kings of the current dynasty. Although the current and previous Thai king kept alternate residences, the Grand Palace is still used in its ceremonial functions, and is still an active palace with working offices for the Royal Household Bureau. Visitors are generally not allowed to enter the palace, but are allowed to walk around and admire the beautiful building and grounds.
The Temple of the Emerald Buddha - Wat Phra Kaew
The main site to see, however, is not the Grand Palace, but rather Wat Phra Kaew, the Temple of the Emerald Buddha. Wat Phra Kaew is not only one of the most beautiful temples in the world, it's also the most important holy site in all of Thailand.
If you have time and the money to spend, a visit to Wat Phra Kaew is really best enjoyed with a hired tour guide or local friend who can explain all of the intricate details to you. The palace complex is huge and sprawling, containing many different buildings and decorated with intricate details, statues, and murals all holding special meaning.
The most important spot in the temple, of course, is the building holding the Emerald Buddha itself. No photographs are allowed inside, and you must keep a very quiet and respectful attitude when you are in the presence of this ancient and mysterious statue.
The Emerald Buddha
Throughout its long and mysterious life, the legendary Emerald Buddha has journeyed from ancient Ceylon (modern Sri Lanka) to the halls of the Khmer Empire's Angkor Wat, to the kingdoms of Laos, Chiang Mai, and Ayutthaya. Now, the Emerald Buddha sits proudly in a place of high reverence and honor at Wat Phra Kaew, Bangkok's royal temple, and a place fitting an image of such power and importance. The Emerald Buddha is considered so holy and important in Thailand, that it may only be approached by the Thai King during special ceremonies throughout the year.
Other former Emerald Buddha temples:
If you live in Bangkok, it would be worth it to visit the Emerald Buddha thrice in one year. The statue has three different outfits that indicate the season: the hot season, rainy season, and cold season respectively. The outfits are changed three times in the year in a special ceremony presided over by the King, the only person who is allowed to touch the Emerald Buddha.