The incorrect form is "broaden your horizons" as there can only be one horizon.
Edit from another user: There may only be one horizon, but that's hardly relevant in a metaphor. The common usage is "horizons," which is also what all the online references I checked say.
Go out and explore new areas. Broaden your horizons. Expand your repertoire.
The adverb form of "broaden" is "broadly." It describes the manner in which something is done in a wide or extensive way. For example, one might say, "The concept was discussed broadly to ensure everyone understood."
It is correct
It is correct to say them both, but it matters on what you want to say.
no it is not correct to say enjoy your vacations
Go out and explore new areas. Broaden your horizons. Expand your repertoire.
horizon
Léaslínte
you could say the horizon is a rizen' (as in the horizon is becoming higher)
Horizont
its ορίζοντας (horizontas)
We say that it sets.
When the sun sets over the horizon, we say that the day is coming to a close or that night is falling.
The adverb form of "broaden" is "broadly." It describes the manner in which something is done in a wide or extensive way. For example, one might say, "The concept was discussed broadly to ensure everyone understood."
horizonte vasto/enorme
Possibly you might say good morning.
It is not correct, you have to say on the beach.