This one took about 3-4 days of stops and starts, blind alleys and many, many small test renders. The large final version took another couple of days to render at high rez on an iMac with the i7 chipset. The program is Terragen 2.
Thanks again for the kind words. I think the illusion works best for mid to distant ranges. It breaks down a bit close up because I'm not using the program to it's full capabilities, but I'm learning. It's not a 'fun' program to use, at least for me. It requires a great deal of patience and commitment, in return it can produce near photographic realism. Visit the Planetside galleries for an idea of what Terragen 2 can achieve (in the right hands).