Why doesn't what I send come to $_GET?

Question

PHP

In $_GET I try to send the string //////page//////page2, and I get page/page2. Meanwhile, //////page//////page2 comes to $_SERVER[request_uri] (this is if the Apache server is spinning). If on Apache + Nginx, then /page/page2 falls in $_SERVER[request_uri], and
why does this happen in $_GET page/page2? is it possible to get a string with all the slashes in a get? Or will $_SERVER[request_uri] have to be parsed when processing addresses?