

Great Wall of China is in the province of Beijing?
Hello! My husband, my parents and I are going to visit Beijing at the end of March. We are flying from Athens (Greece) to Beijing on 23/03/2020 - 13:10 (we will land in Beijing on 24/03/2020 - 04:30). Then we are flying from Beijing to Osaka on 26/03/2020 - 08:40 in the morning. That makes a total of 52 hours. We have already got our tickets and seats and we leave from the same airport that we arrive, Beijing Capital Airport (PEK). We have also booked a hotel in Beijing.
After 10 days we travel back from Osaka to Athens and we stop in Beijing for 4 hours, in which we won't leave airport.
From what can I tell we do not need a visa for Beijing. But can we visit for half a day, during our stay, the Great Wall of China or this is forbidden because as travellers we are only allowed to visit the province of our arrival?
Thank you very much in advance