Fantasy vs. Science Fiction

...As an alternative to the rather tiresome elves and goblins...

I see that for most people, the concept of fantasy is associated only with various fairytale and mythical creatures – they can't imagine anything more (not directed at the author of the post). Here's an explanation from Wikipedia:
"Fantasy works most often resemble historical adventure novels, set in a fictional world close to reality. Unlike science fiction, fantasy does not try to explain the world in which the action takes place from a scientific point of view." So, a huge number of works by various writers, who wrote about real life, possibly with a touch of mysticism, in a fictional world, fall under this definition. This includes Burroughs' Martian stories, and the works of Green, Robert Howard, and many other writers (including writers of other genres). There are no mythical creatures there, as in Tolkien's works, but the action takes place in a fictional world, either in the not-so-distant past or many thousands of years ago. The only thing missing is scientific explanations, which, by the way, makes it easier to read.