This is totaly application dependent. As @iain pointed out, your webserver almost certainly logs all requests. E.g. if you use apache, than you can find the logs in the /log/ folder in the apache directory.
application-dependent: if you have tons of requests, you may face problems keeping your logs for a extended amount of time. Check your webservers config for the logging-policy.
here is an example of how apache commonly logs requests:
184.108.40.206 - - [07/Mar/2004:16:05:49 -0800] "GET /twiki/bin/edit/Main/Double_bounce_sender?topicparent=Main.ConfigurationVariables HTTP/1.1" 401 12846
220.127.116.11 - - [07/Mar/2004:16:06:51 -0800] "GET /twiki/bin/rdiff/TWiki/NewUserTemplate?rev1=1.3&rev2=1.2 HTTP/1.1" 200 4523
18.104.22.168 - - [07/Mar/2004:16:10:02 -0800] "GET /mailman/listinfo/hsdivision HTTP/1.1" 200 6291
22.214.171.124 - - [07/Mar/2004:16:11:58 -0800] "GET /twiki/bin/view/TWiki/WikiSyntax HTTP/1.1" 200 7352
the lines are formated like this, though it varies depending on the logformat you configured:
IP -- [DATE] "REQUESTSTRING" HTTPRETURNCODE SIZEINBYTES
(check out this for more information on the format of the logs)
hope i have helped