Are the sightseens open everyday?

Question

What are the opening days and hours of the most popular sightsee ex.Coloseum, in January?

Answer 1

They could be closed on January the 1st and the 6th. The rest of the days everything should be open except for the churches that might be closed  for turists at Mass time. In Italy everything closes early, so after 5:00-5:30 p.m. most popular buildinds might be closed.

Answer 2

here you are the opening hours and days:

Colosseum: 09:00-16:30 open everyday

galleria Borghese: 08:30-19:00 closed on Monday

galleria nazionale d'arte moderna e contemporanea: 08:19:30 closed on Monday - Saturday is open 09:00-23:00

as you see, most of them are closed on Mondays, that day in which usually Italian shops open just for half day.

here you are more information, you can find the opening times of all the museums and even the prices:

http://www.museidiroma.com/