This one is for the Christadelphians. Our science readers won't be able to get it and the Ex-Christadelphians won't care what the answer is; much less try to work it out. :)
I've never known a Christadelphian who could answer this; but maybe one of you can figure it out.
Answer in three days if you don't get it before. Answers in the comments below please.
Revelation 6:9-11 speaks of "Souls under the altar."
9And when he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held: 10And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? 11And white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellow servants also and their brethren, that should be killed as they were, should be fulfilled.
How can you get underneath an altar and how does this demonstrate that the writer had an intimate knowledge of the Second Temple in Jerusalem?