Singapore was China's largest foreign investor in 2018 — and it was for the sixth consecutive year, according to the city state's trade ministry.

One major investment boost came from the Sino-Singapore Guangzhou Knowledge City, a sprawling project that will convert farmlands into a sustainable urban development expected to eventually be home to half a million people.

The project is a 50-50 joint venture between Singapore-government backed, Ascendas-Singbridge and China's Guangzhou Development District Administrative Committee.

CNBC visited the site which began construction about five years ago and is now has a number of half-built high-rise buildings against a silhouette of cranes. It's located some 45 minutes by car from the Guangzhou, the third largest city in China, which recently connected its massive rail network to Knowledge City's new trains.

The first phase of the knowledge city has just been launched. It was built for about 80,000 people living and working across slightly more than two square miles, and in this phase alone, there will be18 schools.

When completed, Knowledge City could eventually cover an area that's nearly 50 square miles — almost the size of Pittsburgh city in Pennsylvania.