Looking for something new, yet also old and authentic in the Thai capital? Then visit Thonburi, Bangkok's "left bank". "Even the tuk-tuks are cheaper here," says my Thai tour guide, Amy.

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Thonburi (pronounced "Tonbury") on the west bank of the Chao Phraya River is overlooked by many visitors. After crossing by ferry, we begin our exploration in a historic little Thai-Portuguese enclave called Baan Kudichin, also known as Kudeejeen. The name means "Chinese shrine village," but we're here for cake rather than prayer.

We stroll through narrow alleyways, past centuries-old teakwood houses, to the Thanusingha Bakery, the first foreign bakery in Siam. Their specialty is "Kanom Farang"—a sweet treat for foreigners. For over 200 years, this family business has been making a traditional delicacy from simple ingredients—duck eggs, sugar, and flour—baked in cupcake molds.

We sample some of the delicious tarts and then continue on to a nearby landmark on the riverbank, the domed Santa Cruz Church, built in 1770 by the Portuguese-Thai community. It's still early in the day and the church isn't open yet, so we head to the gleaming white stupa of Wat Prayurawongsawat.

In 2005, the abbot noticed that the famous 60-meter-high spire of his temple was leaning. To prevent the venerable spire from becoming Bangkok's Leaning Tower, engineers ingeniously stabilized it from the inside. We enter the hollow, brick-lined stupa—a wonderfully tranquil place that also houses a small museum.

On the waterfront promenade stands the old Chinese temple Kuan An Keng, which, like the Catholic church, dates back to the reign of the Siamese warrior king Taksin the Great (1767–1782). He founded a new capital in Thonburi, and naturally, a shrine—a magnificent bronze equestrian statue—stands here in his honor.

Bangkok was once known in Europe as the "Venice of the East," a reference to the khlong canals that connected the city's districts. We board a rua hang yao – a longboat – for a canal cruise that takes us into the heart of old Thonburi.

On the Khlong Bang Luang canal, we disembark at Baan Silapan, the Artists' House, a traditional teakwood house on the canal that now houses a gallery, theater, and café. A delicious Thai lunch precedes our visit, followed by a performance of classical Thai puppetry. Masked puppeteers manipulate large marionettes depicting episodes from the Ramayana epic.

Our last stop is the extraordinary Museum of Royal Barges, which houses the Crown's longboats (the term "barges" doesn't do justice to these magnificent vessels). On rare royal occasions, a parade of these stately boats rows up the river, rowed by singing sailors in traditional dress.

It is one of the world's greatest processions. In the meantime, visit this museum, which is open to the public, and see the fleet of intricately designed "barges" that are either resting there or undergoing restoration.