If you head east to El Centro from San Diego, Interstate 8 takes you through arid scenery, climbing to 4,000 feet through barren mountains so fast that your ears pop. Then comes the oasis.
As you head down rapidly out of the mountains once more toward El Centro you hit a sign that tells you that you have reached sea level. Green fields and palm trees, stacks of hay drying in the fierce sun -- 90 degrees Fahrenheit even in November -- surrounded on all sides by rocky hills and the desert.
We knew before coming here that this was an agricultural region, but the lush greenery amid such a scorched landscape took us by surprise. This is where much of America's lettuce, spinach and other vegetables come from in the winter. There are also large cattle feed lots here too, which launch a frontal assault on your olfactory system long before you see them.
But you don't have to wander far from the fields to find the desert and its fine reddish, beige sand and realise just how incongruous the lush green fields are. Particularly when you feel the sun beating down on you when much of the northern hemisphere is already feeling the first cold of winter.
This is all made possible by water rights this area has from the Colorado River. As this part of the desert is below sea level in some parts, the water flows downhill and an irrigation system delivers it to 500,000 acres of farmland.