Specifically the horizon as seen over land, in contrast to 水平線 which refers to the sea horizon.
See also: 水平線
The sunset sinking below the horizon is beautiful.
On the wide plain, you can see the horizon far away.
I watched the setting sun sink below the horizon.
The morning sun rose over the horizon.
Standing in the plain, you can see the horizon far in the distance.
There's apparently a small village beyond the horizon.