El Dorado - what do you make of it?

Seemingly a very simple poem, yet it has always intrigued me. I don't think I got deep enough after analysing it.

Here it is:

Gaily bedight,
A gallant night
In sunshine and in shadow,
Had journeyed long,
Singing a song,
In search of El Dorado.

But he grew old --
This knight so bold --
And -- o'er his heart a shadow
Fell as he found
No spot of ground
That looked like El Dorado.

And, as his strength
Failed him at length,
He met a pilgrim shadow --
"Shadow," said he,
"Where can it be --
This land of El Dorado?"

"Over the Mountains
Of the Moon,
Down the Valley of the Shadow,
Ride, boldly ride,"
The shade replied --
"If you seek for El Dorado."

It must be an allegory for something more than El Dorado, right? And there's definitely death involved. I'd like to hear what you have to say about this poem.

I think it is about trying to chase dreams that are not real, or could never be, and your life slipping away from you, becasue you are own a hopeless quest.

I noticed the frequent use of the word "Shadow" I think El darado is the shadow, it is a thing that follows you around almost huanting you, and yet something you can never truly grasp.

Thanks, Dark Muse! Yes, the shadow is quite a frequent motif in Poe, not only as a representation of evil but also in the Doppelgänger sense. And that's a great touch of yours, by the way, seeing El Dorado as the shadow itself - kind of reminds me of the Dracula in the 1922 film "Nosferatu" pretending to be some kind of scout, leading the protagonist to himself (i.e. to the Dracula).