Layover in Guangzhou - 16 hours

China Southern changed my flight at the last minute, and now I have a long layover of nearly 16 hours.

I’ll be arriving from Europe en route to Vietnam, and I believe I can take advantage of the "Transit Without Visa" (TWOV) policy.

Is it doable to hit the city's main highlights? figuring it'll take around 2 hours to clear immigration/get out of the airport and needing to be back 3 hours before my flight, I'll have about 11 hours of free time to explore. Is that enough?

What do you guys recommend? what are the must-see spots?

Thanks in advance