Until recently I hadn't thought about it much, but the doors of most of the churches I've attended over the years have been red. I'm not talking brick red here, or maroon, or burgundy. No, it's closer to a bright fire engine red. I am Episcopalian, but recently I started noticing that the doors of many other kinds of churches - mostly mainline Protestant churches like Lutheran and Methodist - are also red.

One explanation I heard when I set out to find out why the doors are red is that red doors indicated that the mortgage is paid. I also heard that red doors indicate that the mortgage has not been paid off yet. But both of these explanations stem from a long-running joke, and don't really explain the significance of the red doors.

Another thing I heard a lot is that the red doors represent sanctuary, a place of safety and refuge. Holy ground is beyond the red doors, and those within may not be harmed. The red doors represent protection from physical and spiritual evil.

Okay, says the four-year-old in me, but why?

In the more liturgical Protestant denominations (such as Episcopal, Lutheran, or Presbyterian), and I imagine also in the Catholic and Orthodox churches, red is a color that is traditionally reserved for times such as Holy Week or Pentecost.

So red doors indicate the presence of the Holy Spirit, which descended on the apostles 50 days after Easter, an event called Pentecost which moved everyone who witnessed it to convert to Christianity. Red doors also represent the Blood of Christ, shed for the forgiveness of our sins, which protects us from the wrath of the cranky Old Testament God.