Viva Las Vegas

'I am a sinner," confesses comedian Johnny Vegas as he embarks on a spiritual journey in the US to save his soul. The son of a devout Catholic, he studied for the priesthood for 18 months before turning to funny business. So he's a more suitable guide than you might at first think, and he does seem to be having some sort of crisis of faith as he reaches his mid-thirties.

The opportunities are there, as he himself admits, to take the p*** out of American evangelicals, whose numbers now mean they have the power to vote in a President.

And things don't start well. Vegas has one last taste of sin on a drunken night out in Las Vegas. His hangover the next day is obvious. "I'm being punished, I know I'm being punished," he says, looking the worse for wear.

Despite this unpromising start, his search for new meaning in his life turns serious. He seems genuinely moved, both emotionally and spiritually, by some of the things he discovers and people he meets.

"I suddenly felt very envious of the people in there, they had somewhere to go," he says after attending a service with families who've moved to Colorado Springs - "the Jerusalem of the evangelical movement".

Vegas seems to be tired of playing up to his popular image of the lovable, boozing, smoking joker. "The public image of me I like to court, but I know it's not me, but I can't kid myself any more," he says.

He can't quite bring himself to change. By the end, he's telling us: "I learnt a lot, but wasn't sure what I brought away from it." But the experience proves a surprisingly fresh and candid celebrity quest for self-enlightenment.

In The Aztec Massacre: Revealed, archaeologist Dr Elizabeth Baquedano is looking for answers too - the story behind the 400 skeletons found, after 500 years, in a mass grave in the ruined city of Zultapec in Mexico.

The "dark and diabolical secrets" we're promised emerge as ritual sacrifice and dismemberment. Descriptions and reconstructions go as far as they can in a pre-watershed slot in bringing the acts of sacrifice to life.

Four priests would hold down the victim as the chief priest plunged a knife into the sacrifice's chest, pulled out the still-beating heart and offered it to the gods.

Severed heads were put on a skull rack, like beads on an abacus, and displayed for all the townspeople to see.

As well as making offerings to the gods, these rituals served to remind the people of the Aztecs' power.

There's also evidence that victims were chopped up and eaten. Marks on the bones proved this.

Bones also helped identify victims of the World Trade Centre terrorist attack as 9/11: Into The Underworld revealed. The documentary details the disturbing, often grisly, work involved in identifying victims from remains found buried in the rubble on the Ground Zero site.

Beneath the Twin Towers was a six-storey underground complex of shopping mall, car parks and two subway stations. When hope of finding more people alive was gone, the operations team determined to identify as many of the victims as possible. Professionals and volunteers searched for months in the caverns and passageways beneath the tangled mesh of concrete and steel.

Some were looking for evidence of relatives, others for friends lost in the tragedy. DNA samples of missing people were used to identify remains found. This wasn't an easy task. Some people were vapourised in the explosions and no trace remained. Other remains were found on the rooftops of surrounding buildings.

But more than 1,500 people have been identified of the 2,749 people thought to have died.

For friends and relatives of those who've been named, identification comes as a relief. Rosemary Cain, whose son George died, says that when she was told: "I was not upset, I didn't cry. I just felt like looking up at the stars on a bright clear night - and there were a million stars in the sky - and just saying, 'thank you, God'."