We start the penultimate episode of this rather wonderful series with a balloon ride across the Rio Grande in New Mexico. For those of you who missed it, the full episode is already available on the ever dependable BBC iPlayer here. This weeks episode has Stephen travelling from New Mexico, through Utah, Nevada, Arizona and finally arriving in California. Experiencing the cutting edge of science, the spiritual Monument Valley and much more in the space of the hour long episode.

After the aforementioned balloon ride we touch down and head to see some rather awe inspiring sustainable houses. These building have been around for thirty eight years and are designed to be highly self sufficient, using plants, recycled water and solar panels to take care of pretty much all the needs of a small family. There's very little waste in these, apart from the waste used to construct the walls surrounding the property, which are made from a mix of mud and discarded bottles or cans. It's a glimpse into one potential future for humankind, a future we may be forced into unless there is a major breakthrough in resource management, power and recycling within the next decade or so.

After touring these houses Stephen heads to Los Alamos, home of cutting edge research and the birthplace of nuclear power, where he is shown a high powered electron microscope and we learn a little about their research into quantum based computers and self repairing materials. Also mentioned is the potential of dark matter, my personal favourite form of dark matter is in Futurama and powers the Planet Express Ship.

Next up is Monument Valley in Nevada. A beautiful and spiritual place that has been the backdrop for many westerns. Stephen spends some time with the Native Americans there; trying a little basket weaving and then having a meal with them after a somewhat dusty walk. Following that he takes a trip on the Colorado River, which is an entirely artificial construct, evidenced by nature's lack of presence there right now. After enjoying another meal he's taken by the boat captain to see the world's largest natural bridge. The Rainbow Bridge is so large that the Statue of Liberty could be placed underneath it. Which is a sight I'd quite like to see if I'm honest. A big French lady lurking under a bridge is a familiar sight to anyone who's spent any time in Paris.

My joking aside Stephen next travels to Arizona via a B-17 Flying Fortress, landing at a base where several billion dollars worth of planes are retired. Kept sealed up in case they are needed in the future, they ain't dead yet, just sleeping (or out borrowing birds possibly). From here it's off to Old Tucson Studios, Hollywood's home of western filming, Stephen gets a chance to swagger about town and engage in a little gun play against a mean sheriff and his deputies, I shan't disclose who comes out of it alive but remember that Stephen has only died on screen twice (In The Young Ones and Black Adder goes Back and Forth) and off-screen an additional three times.

In Las Vegas, Nevada Stephen takes part in one of the newest forms of business entertainment management type exercises. Spy Games, he's posed as the mole and has to sabotage the efforts of his fellow spies, the odds are a little stacked against him because he's already the outsider of the group - the rest of his companions are all not only Americans but all members of the Chippendale's. He is found out fairly quickly but does try and have a good go at it. He then goes to talk with some Mormons who are photographing a Mormon Calendar and we learn a little about the Mormon faith along with the misconceptions people have about it.

In Virgina City Stephen visits a legal whore house, an award winning one no less. Where he learns about how the age old business of prostitution is undertaken when it's held up into the light. It's true that there is no getting rid of this part of society and the brothel is a surprisingly pleasant and attractive looking place. I still found the whole business very seedy, but it's a great example of what can be done to make the business safer for all involved. Oh and this way it gets taxed, which is always a good thing for society in general. Still it's a touchy subject for many, but we needn't worry here as the show doesn't attempt to crusade for the legalisation of prostitution, instead it just reveals and enlightens. It's also amusing how uncomfortable Stephen obviously is in here, especially when the "DC" is explained to him.

Last of all Stephen drives past Lake Tahoe and arrives at the Pacific Ocean in California, all ready to head North for the final leg of his journey next week.

The episode felt a lot less rushed than many of the previous ones, due to the size of the states involved there was more time to look in detail at them. It's a full twenty minutes before we even depart New Mexico, which is a nice change. The slower pacing and greater detail contributed a lot towards making this one of the best episodes of the series. But still not all states were treated equal and at times I did find it a little difficult to keep track of which state Stephen was in. But it was undoubtedly a lot of fun to watch and educational to boot.