Drupal has a number of default paths that are created automatically:

/node/3 : Node with id of 3

/user  : User login screen, or user profile if already logged in

/user/3 : User with id of 3

/user/password : Request new password

/user/register : Create a new account

/user/login : Login page

/blog  : Blog summary for site

/search : Search page

/admin/content/node-settings/rebuild : Rebuild permissions for site.