I was driving on the 91 East Freeway during the early afternoon. I saw what I thought was the local blimp off in the distance hovering. As I got closer, it no longer appeared the be a blimp, but a metallic, cube like object with jagged protrusions. I was attempting to track it and drive. I was able to look at it off and on for about 3 minutes. As I got a bit closer I knew it was not a blimp nor a large suspended balloon. My eyes welded with tears out of disbelief. I also witnesses other people on the freeway looking up to try to see it. Eventually I lost track of it due to the direction of the freeway and never caught sight again.