Learn Spanish (Latin America): Hace una hora que vigilo el pasillo. - I have been guarding the hallway for an hour.

In Spanish, when an action started in the past and is still happening right now, you use the present tense. The structure hace + [amount of time] + que + [present tense verb] literally translates closer to "It makes [time] that I [do action]." Since you are still guarding the hallway right now, vigilo stays in the present indicative.

Could I phrase this sentence differently without putting hace at the beginning?

Yes! You can flip the order and use desde hace (for / since [amount of time] ago). The sentence would become: Vigilo el pasillo desde hace una hora. Both structures are very common and mean the exact same thing.

I know mirar means to look or watch. How is vigilar different?

Vigilar implies watching over something with a sense of security, guarding, or monitoring. You use mirar or ver to watch a movie or look at a painting, but you use vigilar to guard a hallway, keep an eye on a boiling pot, or monitor a suspect.

Can pasillo be used for other types of "halls" or "aisles"?