From the online American Heritage Dictionary, some of the definitions of horizon are:
1. The apparent intersection of the earth and sky as seen by an observer. Also called apparent horizon.
2. The limit or edge of the observable universe. (Astronomy)
3. The range of one's knowledge, experience, or interest.
What's on the horizon?
I am expanding my horizon.
I am leaving one behind,
and traveling towards another.
Where is your horizon?
Check out more horizons
at the 52 Photos Project.