24h stop over ticket in Beijing , visa?

Hello there,

I am a greek citizen with eu passport and now travelling in japan.
In 4 days , Wednesday, I want to fly from tokyo to Bali.
I fly with china eastern and with a 24hrs stop over in Beijing!
So I want to go and visit the Great Wall of china at that time.

Should I pass all this entry procedure (that I think it's not possible due to limited time)??
And what exactly should I do?

Looking forward your reply please.

Chris