Visitors walk the hotongs with Beijing Hutong Trips.[Photo provided to China Daily]

For an ancient city like Beijing with many must-sees, foreign tourists know the major sites that they will set foot on. However, for some, the hidden gems in secret corners of this sprawling metropolis are what they really need to see.

After living in Beijing for three and half years, Cesar Casellas Martinez saw the untapped opportunity of offering an authentic local tour service, jumped off the wagon of working for a tour company and started Beijing Hutong Trips with a Chinese partner.

Starting in January, the 34-year-old Spaniard designed eight different walking tour routes, two bike tour routes and sidecar routes. Each route was designed for different needs, with one purpose – to help visitors explore authentic local life in Beijing.

"Being a photographer and a tourist guide, I’m always trying to find ways to combine my passions. With this project I could offer something special to expats who want to see the real Beijing, " he said.

Cesar Casellas Martinez, co-founder of Beijing Hutong Trips.[Photo provided to China Daily]

At first he gave free tours to friends in Beijing, but through word of mouth, more people turned up for the excursions. Now offering tours from 190 yuan and up, Martinez leads the way through hutongs, a network of labyrinthine lanes and alleys in the city's center. Staying away from the most commercialized and touristy spots, he always manages to wow visitors with old houses tucked away in ancient alleys, local restaurants offering authentic flavors that aren't in restaurant guide books and newly-sprung Western-style brew pubs and cocktail bars scattered on old streets.

"When I first started, I just wanted to build good social networks with businesses as well as establishing a good image for my company for long-term development, so I'd offer trial tours for free. Now people have seen it, they like it, and they recommend me to others, so our business is now growing, " he said.

"Since we offer tours in Chinese, English and Spanish, we even have local Chinese participating on our tours to see their city in a fresh angle," Martinez said.

Andrea Gottschalk, an expat who lives in Beijing, found Casellas' tour a great way for her to re-discover Beijing.

"The bike tour has been one of the best experiences I've had, being able to see the hutongs from within with Casellas' comments and explanations is a must-do both for tourists and expats, " she said.