Nineteenth-century photographs of Bangkok portray the busy life on the Chao Phraya River, where a ragtag range of vessels -- from humble rowboats to sailing ships -- crowded the busy port. This was the original gateway for early foreign visitors who traveled upriver from the Gulf of Siam. Rama I, upon moving the capital city from Thonburi on the west bank to Bangkok on the east, dug a series of canals fanning out from the S-shaped river. For strategic reasons, the canals replicated the moat system used at Ayutthaya, Siam's previous capital, in the hopes of protecting the city from invasion. The city waterways represented the primordial oceans that surrounded the Buddhist heavens. A small artificial island was cut into the land along the riverbank and became the site for the Grand Palace, Wat Phra Kaew (the Temple of the Emerald Buddha), and Wat Po. To this day, this quarter is referred to as Ko (island) Rattanakosin. This is the historical center of the city and the main tourist destination for day trips.

The canals, or klongs, continued eastward from Rattanakosin as the city's population grew. Chinese and Indian merchants formed settlements alongside the river to the southeast of the island. The mercantile district of Yaowarat (Chinatown) is a maze of busy back alleys. Its main thoroughfare, Charoen Krung Road (sometimes called by its former name, New Rd.), snakes southward, following the shape of the river. On the eastern edge of Chinatown, you'll find the arched Hua Lamphong railway station, a marvelous example of fanciful, fin de siècle Italian engineering.

Just beyond Yaowarat, along the river, lies Bangrak district, where foreign interests built European-style residences, trading houses, churches, and a crumbling colonial Customs House. The Mandarin Oriental Hotel, the Grande Dame of Bangkok, sits among them, one of the few great heritage properties left in town. Bangrak's main thoroughfares, Surawong Road, Silom Road, and Sathorn Road, originate at Charoen Krung, running parallel to Rama IV Road. Within Bangrak, you'll find many embassies, hotels and high-rises, restaurants, and pubs, as well as the sleazy nightlife at Patpong or glitzy gay clubs in Silom Soi 4.

Back to Rattanakosin, as you head upriver, you'll hit Banglampoo, home to Bangkok's National Museum, Wat Suthat, the Giant Swing, and Klong Phu Khao Thong (Golden Mount). Its central point is Democracy Monument, a roundabout where the wide Ratchadamnoen Klong Road intersects Dinso Road. Around the corner is Khao San Road, which was once solely a backpacker hangout. It still has budget accommodations, inexpensive restaurants, lots of tour agents, and good nightlife, and it's hanging onto its 1970s hippy flavor -- but is also heading into the mainstream. Starbucks, Burger King, and Boots are all muscling in on the once funk-filled, alternative vibe here.

Farther north of Banglampoo is leafy Dusit, home to Wat Benchamabophit, Vimanmek Palace, the Dusit Zoo, and parks.

As Bangkok spread on the east shore of the river, Thonburi, the former site of the capital across the river, remained in relative isolation. While Bangkok was quick to fill in canals, ushering in the age of the automobile, residential Thonburi's canals remained, and a longtail boat ride through the area is a high point of any trip here. Thai riverside homes, both traditional and new, and neighborhood businesses (some housed in floating barges) reveal glimpses of life as it might have been 200 years ago. Access to Thonburi's Bangkok's Southern Bus Terminal is via the Phra Pinklao Bridge from Banglampoo.

Back on the other side of the river, Bangkok grew and fanned eastward. From Ko Rattanakosin, beyond Bangrak, lies Pathumwan, known for its huge market. This is where the famous American journalist and silk connoisseur Jim Thompson once lived. His stunning Thai-style house is now open to visitors. Nearby is busy Siam Square, with its myriad boutiques and huge shopping malls. This area's hotels, cafes, and nightclubs attract scores of local teenagers and students. Beyond Pathumwan, Wireless (Witthayu) Road runs north to south, between Rama IV Road (at the edge of Bangrak) and Rama I Road (at the edge of Pathumwan). Here, the huge U.S. Embassy complex stands just meters from a clutch of five-star hotels and chic shopping centers such as All Seasons Place and Central Chidlom.

From Siam Square, Sukhumvit Road extends due east, its length traced by the BTS. Many expatriates live along the small side streets, or sois, that branch out from Sukhumvit. This area is lined with tourist restaurants and entertainment spots, shops, and big malls -- you'll find luxury hotels alongside inexpensive accommodations, fine dining, and cheap local eats, as well as clothing stores and streetside bazaars. (Be aware that there are also lots of schemers in this area.) Easterly situated Sukhumvit is mostly a major commercial center and much of it is connected by the overhead BTS. Bangkok's Eastern Bus Terminal is at Ekkamai BTS, on Sukhumvit Soi 63.

Finding an Address -- Note that even-numbered addresses are on one side of the street and odd-numbered ones the opposite, but they are not always close to each other. So 123 and 124 Silom Rd. will be on opposite sides of the street, but possibly 300m (nearly 1,000 ft.) or even farther apart. Most addresses are subdivided by a slash, as in 123/4 Silom Rd., which indicates that a particular plot has been subdivided into several sections. Some addresses also include a dash, which means that the building itself occupies several plots. You'll find the term thanon frequently in addresses; it means "street" in Thai. Soi is a lane off a major street and is either numbered or named. If you are looking for "45 Sukhumvit Soi 23," it means plot 45, on Soi 23, off Sukhumvit Road. On Sukhumvit Road, even-numbered sois will be on the south side and odd-numbered sois on the north side.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.