what is the directory structure for removable media and what are their differences according to FHS?

In FHS-2.3, we have /media that holds mount points for removable media such as CD-ROMs and we have /mnt that holds temporarily mounted filesystems.

On the other hand, we have /run/media and /run/mount. For me, the CDs and USBs are mounted on /run/media.

I don't see any clear distinction between them(/media, /mnt, /run/mount) . What are their differences?

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I have seen similar trend (mount on /run/media) in fedora 20 - GNOME 3.10.4 and ubuntu 14.04.1 (installed on virtual box) with GNOME 3.10.4. But when I plugged in a USB flash (with auto-mounter script) on a system with Centos 6 and GNOME 2.28.2 it was mounted on /media