China in 1920 and then again in 2009. Dheera Venkatraman

Over the past 30 years, China has grown from an agricultural-centric country to a largely urban society. Hundreds of millions of rural residents have left the countryside for larger cities, many in the hopes of finding better jobs.

Photographer Dheera Venkatraman spent a few years traveling around the country to create a series he called "Time Traveling in China". The project involved finding images from the 1900s and revisiting the locations they depicted, taking his own photos of what the landscape looks like today.

"Having studied physics before, I thought doing a trip in time, instead of space, might be an interesting thought," Venkatraman told Business Insider.

Below, see 13 images of the drastic changes China's landscapes have undergone.