how to connect an old external drive to new iMac?

I just bought a new iMac, the basic one with the 21.5 inch monitor. I have a Lacie external drive. The back of the external drive looks like this:

I don't need this to be connected to the iMac constantly, this is an archive drive, everything on this also exists on another, larger drive which is my main external backup drive. But I do still want to be able to access this drive, in case the main backup crashes or in case I decide to repurpose it. What is the easiest way to connect to this drive? I don't think it has a USB 2.0 port and I don't see any other ports except for a camera or ethernet on my new iMac.