Last year, Bangkok attracted 21.5 million visitors, making it the world’s most popular travel destination. So it can pay explore the city’s lesser-known quarters. Here’s our list of the best things to see to get away from the crowds.

Thonburi: The old capital

“On this side of the river you get the best views of Bangkok because there are no other buildings around us,” says Christian Hoechtl.

He is the general manager of Avani Riverside Hotel, a new hotel in a skyscraper in Thonburi – the land east of the Chao Praya River. “Because Thonburi is where Bangkok was founded, it has many secrets,” he says.

To help uncover some of those secrets, I call an expert, Chin of Chili Paste Tour, a former school teacher who takes food and history tours in Thonburi.

My day with Chin kicks off with a boat ride across the Chao Praya River. Instead of hitting Wat Arun, the Temple of Dawn, one of the most photographed sites in all of Thailand, we visit nearby Wat Rakhang, the Temple of Bells, a place few foreigners know of.

A symphony of bells greets visitors at Wat Rakhang; they are rung by devotees to bring them luck in business.

Chin, of Chili Paste Tour, enjoys a duck soup in Thonburi. Photo: Supplied

Inside the complex is a 250-year-old teak house containing the library of King Taksin, the monarch who moved the Thai capital to Thonburi after the old capital Ayutthaya was sacked by the Burmese in 1767.

The library’s walls are covered in frescoes depicting life in Ayutthaya: ancient arts such as puppetry, noodle-making and copper bowl-crafting that are still practised in Thonburi. And Chin knows exactly where to find them, including a hole-in-the-wall that makes one of Bangkok’s best duck-noodle soups.

“Thonburi still feels old,” Chin says over lunch. “Even this food, duck noodles, was a speciality of King Taksin’s people.”

Avani Riverside Hotel Bangkok, rooms from $107, minorhotels.com/avani

Chili Paste Tour, $180 for two people or $113 for one person, foodtoursbangkok.com

Bang Krachao: The green lung of Bangkok

Bang Krachao is an artificial island that Thailand’s late King Bhumibol turned into a park in the 1960s to give locals a place to get away from the big smoke.

It’s huge – 16 square kilometres – so the smartest way to see it is on two wheels, perhaps with The Other Side of Bangkok. It’s a tour company formed last year “to show tourists unique places they can’t easily find by themselves”, according to owner Peach.

To ensure I don’t get lost, The Other Side sends a driver to pick me up from my hotel and takes me to Bangkok Port, 10 kilometres south of the CBD, where I rendezvous with Peach.

From there, a long-tail boat whisks us across the Chao Praya River to a rickety wooden jetty on the eastern shore. The reward is a sudden slice of rural Thailand – a quiet calm place with bamboo shacks, crumbling old temples and raised walkways that snake through mangrove forests and fruit plantations.

“This land is farmed communally by the local villagers and they make special sweets and ice teas with them at the local market,” Peach says. That’s where we head for lunch.

The Other Side of Bangkok, half-day bike and boat tours of Bang Krachao, $49 per person, othersideofbangkok.com

Peach, from The Other Side of Bangkok, takes tours of the island of Bang Krachao. Photo: Supplied

Phra Athit Road: Bangkok’s Riviera

A short stroll from Khao San Road, Bangkok’s famous backpacker district, is the bohemian riverside district of Phra Athit Road. If you’re not staying on Koh San Road, the quickest, cheapest and most scenic way to get there from just about anywhere in Bangkok is on the Chao Praya River Express Boat. Jump on at Sathorn (Central), Chinatown or the Grand Palace and jump off at to Phra Athit, pier No.13.

The first thing that’ll catch your eye on Phra Athit Road is a large white conical castle that wouldn’t look out of place in an episode of Game of Thrones. It’s Phra Sumen Fort, one of two remaining forts built in the 18th century by King Rama to protect the city from raiders.

An antique shop on Phra Arthit Road, in Bangkok’s river district. Photo: Supplied

The manicured garden surrounding the fort – Santi Chai – is one of Bangkok’s nicest parks. In the mornings you can see senior citizens doing tai-chi, at night it attracts buskers, and the weekend hippy market is crammed with art, books and fashion.

Along the tree-shaded footpath, between a row of old shopfronts reinvented as cafes, barbershops, juice bars and boutiques, is Roti Mataba.

Since 1948, it has done a roaring trade selling mataba, parcels of unleavened bread stuffed with spicy southern Thai curries, and said to be the ultimate fusion of Thai and Indian cuisine.

Chinatown: Bangkok’s new cool

“When I started working here, only Chinese tourists would come to Chinatown. But now tourists of many nationalities have started come here to try the food and see the old beauty,” says Woralak Bangprasert, manager of Shanghai Mansion.

It’s a retro boutique hotel and spa in Bangkok’s historic Chinatown district that invokes the nostalgia of Shanghai in the 1930s.

Outside the hotel’s lobby on Yaowarat Street is a colourful, neon-lit street food market, an extravaganza dishing up Peking duck, fried crab, bird’s nest soup.

Head south to Kuan Yim Shrine, where an intricate red arch leads to a soulful 200-year-old Chinese temple. Across the road is an even more impressive sight – Wat Traimit,  the Temple of the Golden Buddha – a soaring white palace home to a five-tonne solid gold Buddha statue, the largest of its kind on earth.

Behind Wat Traimit is a maze of candy-coloured terrace buildings concealing Soi Nana (Nana Lane), a compression point of shabby chic cocktail bars spreading like the tentacles of an octopus. One of the newest, Ba Hao (No.8) is an Oriental-style speakeasy named after its auspicious address. “In Chinese, eight is a lucky number,” owner Phoom says.

Shanghai Mansion Hotel, rooms from $108, shanghaimansion.com

Chinatown’s Nana Lane hides some of the city’s best cocktail bars. Photo: Supplied