The red candle near the altar

It's quite beautiful how many ornate, interesting, priceless things can be found in Catholic Churches. But the meaning behind all of them is actually the most beautiful part.

A fairly simple, but yet important, one of these symbolic things is that of the red candle found near the tabernacle (which is usually found behind the altar, but has been moved to other areas in many churches now).

This candle, when lit, is what tells us that the nearby tabernacle currently contains the body and blood of Christ in the Eucharist (prompting genuflection and reverence).

If it is not lit, that means that the tabernacle is empty (therefore genuflection is not appropriate).

So look for the red candle first. It will tell you one of the most important pieces of information you need to know when entering a Catholic church.