Do we need a visa if arriving at Shanghai from a cruise and staying for 3 days afterwards?

Arriving in Shanghai on October 17, 2017 via a cruise that originates in Japan and also goes to South Korea. We wish to stay in Shanghai and see more of the sites for 3, maybe 4 days. We would depart back to Canada from Shanghai. Do we require visas for the additional days? Would we be able to take day trips outside of Shanghai? We both have valid Canadian passports.