Who are the most frightening people in the world? High on my personal list would be religious fundamentalists. Two documentaries this week showed just how terrifying such zealots can be.

When I was a child, I spake as a child, but Baby Bible Bashers (Channel 4) showed us three children who speak and behave as if they are adult preachers. Two of them are American - Samuel from Mississippi and Terry from Florida. Seven-year-old Samuel gave his first sermon when he was three. Like his parents, he believes that fornicators, adulterers, homosexuals and hypocrites are all damned and will be "cast into the lake of fire". Samuel gets beaten by his parents whenever he disobeys them, because "disobedience deserves punishment". Nine-year-old Terry not only preaches but also gives healing - and he is already being hailed as the new messiah. Terry's father has ambitious plans for him - including making money by selling T-shirts and signed photos.

In Brazil, Ana Carolina Dias started preaching when she was three and now addresses crowds of thousands. Like the two American boys, her preaching style is to shout very loudly. In the case of all three children, it looks as if obsessively evangelical parents are usually to blame for the way their offspring behave - but it is still very disturbing.

The End of the World Bus Tour (BBC2) accompanied a group of tourists who are on a ten-day tour of Israel because they believe Doomsday is imminent and Israel is "God's country". They visit a valley called Armageddon - "God's final battle will take place at this particular site," says Lorna from Kent. Details of the final battle are vague but it apparently involves a lot of bloodshed and God defeating all the ungodly. The tourists assume they are safe because they are all believers, and "the rapture" will carry them up to heaven at the Apocalypse, leaving us sinners to endure eternal suffering (God is love?). Like the youthful preachers described earlier, they all believe literally in the Bible, apparently without any scepticism about this much-debated book.

The tourists then go and help out at an Israeli army base. Barbara tells us: "They have the finest army in the world . . . because they have the finest god." The highlight of the trip is a stay in Jerusalem, where a visit to the Arab Quarter evokes some intolerant remarks from the tourists about Muslims. Producer David Clews concluded that the trip had shown him how the tourists' faith helped them to deal with grief and pain but "it seemed it could only do that by demonising the beliefs of others" - including David's own agnosticism.

Scariest of all was teenage traveller Hannah, who expressed her belief in original sin by asserting that "Man is evil . . . We are all born with an evil heart." And she told Clews her Christian vision of the future: "I get to spend an eternity in God's presence, joint heirs with him, and you get to burn in hell for eternity."

Attila the Hun was another very alarming person with fixed ideas. According to Attila the Hun (BBC1), he was obsessed with accumulating gold by slaughterng people - mainly inhabitants of the Roman Empire. Doing a fair day's work for a fair day's pay didn't appear to have occurred to him. This one-hour drama-documentary seemed much longer than an hour, as Attila fought one bloody battle after another. Computer-generated imagery created a believable cast of thousands but there were too many familiar faces for credibility. The cast even included Ian Lindsay, the ineffectual office worker George from Men Behaving Badly. The programme unsuccessfully tried to portray Attila sympathetically, ending with the mawkish comment: "Even though his empire was short-lived, Attila achieved something far greater: immortality. After all, who has not heard of the name Attila the Hun?" And who has not heard of Adolf Hitler, Joseph Stalin and all the other tyrants who held human life cheap?