Down over the mountains and into San Diego. I'm right on the Mexican border now, my phone even welcomes me to the country. Lots of checkpoints on the road , with statistics saying how many illegal immigrants have been stopped on their route into the land of the free.

San Diego is on a beautiful bay by the Pacific Ocean. Drove up to the point for a view over the whole city. It's a very naval city with two aircraft carriers moored in the busy harbour.

My final drive took me up the coast past the mission San Juan Capistrano. A beautiful old settlement up in the hills, founded by Spain in the 18th century. Certainly a relaxing place to finish my coast to coast trip.

Final leg of the journey takes me back over the Colorado River, this time into California. The river used to be miles wide here, expanding over the flood planes around the border. Now it is a far more modest size, with much of the water Bing held in the dams upstream and supplied to irrigate crops throughout two states.

Yama was the main crossing for those attempting to reach the gold fields of south California. Many impoverished settlers were denied entry to the sunshine state and so settled in the area, something the local museums make much off.

Over the bridge you head across the sand dunes towards the mountains. The original road was single track, made of wooden planks and involved an horrendous trip of at least a day to traverse the ten miles, leaving the travellers rather shaken.

The route now passes the history of the world in Granite. All the motors lie events in the history of the universe, etched onto long tablets of stone. It's a remarkable achievement and very informative. I can help but think Donald Trump could do with a visit.

In the heart of Arizona there are really cacti with arms, and road runners scurrying about, although they don't go beep beep.

The drive to Phoenix takes you through some desolate lands, with small communities providing an oasis to the vast desert. It even has dust storms to transverse, adding that frisson of excitement to the desert drive.

Phoenix itself is situated on an expansive plateau, bordered by small mountains. It almost never rains here, and gets unbelievably hot in the summer, but in spring it was gorgeous.

One of the highlights is the Desert Botanical Gardens. Every time of cactus is displayed, Rita a special section reserved for the Saguaro cactus, which only grows in Arizona, and us the classic cactus from the westerns. They are protected in Phoenix, and everyone removed has to be replanted elsewhere.