Can I, a foreigner tourist, walk around the streets of any Chinese city late at night?

I mean, just out of curiosity, can I go around walking everywhere, even late at night, like 4:00 am? I like to walk everywhere and sometimes try to save some money in my adventures around the world. would it be a problem to skip a hotel night and simply walk around to get to know the city? it interesting to me to see the city at these late times at night. though I don't want to get into any troubles.

thanks in advance.