By Jonathan Amos BBC News Online science staff

Like the eager child with their collection of odd stones and marbles, Oliver Crimmen is desperate to show you his haul - and with good reason.

The football fish (H. groenlandicus): From an alien world

The fish curator at London's Natural History Museum has some truly extraordinary items in his care that will simply make your jaw drop when you see them.

For sure, he has some humdrum specimens that can be seen in any fish market around the world - but he also has some real "Penny Blacks": monsters from the deep, Amazonian giants and, of course, the coelacanth, the famous "fossil fish".

And you can see all them from Monday when the museum opens its �100m Darwin Centre to the public.

Open to all

Twenty-two million specimens, from mammals to molluscs, all of them pickled in alcohol, have been moved into the eight-floor state-of-the-art research and display facility.

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Specimens are brought out from the vaults for public display

Previously, this zoological treasure, some of it collected by Charles Darwin himself, had been stuffed in an anonymous building behind the museum's main complex.

It was a closed world; the large jars and tanks of the "Spirit Collection" were only available to researchers - and strictly by appointment only.

"I guess the Victorians thought of my science as a below stairs activity, but we're out in the light now," says Crimmen, who joined the museum from college 30 years ago.

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Inside the Darwin Centre

The guided tours through the dim, cool vaults of the new centre are sure to be the hottest tickets on the London visitors' scene for the next few months. Get over the "urgh" factor and be prepared to be amazed.

Creatures, great and small, are stored in 450,000 jars. The smallest will fit in the cup of your hand; others weigh 60 kilograms and are kept in a "monster" basement known as the tankroom.

Lights in the dark

"My favourite specimen is a deep sea anglerfish with a stalk on its head and a luminous bulb," says Crimmen.

The pirarucu (A. gigas): The largest freshwater fish known to science

"It's called the football fish - it's about the size of a football and the same shape.

"The lights on its head lure prey within reach because it's living in the total darkness of the deep sea.

"It comes from such a different world of massive pressure and darkness and you can tell by looking at it that it is very alien to our own terrestrial habitat - needle sharp teeth, tiny eyes and this amorphous black body totally invisible in the dark except for the little lights."

A "Penny Black": The coelacanth (L. chalumnae)

All life is here, as they say - literally. Evolution has produced all manner of complexity and diversity and nowhere is that more evident than in fish.

"The aquatic environment is so huge," says Crimmen. "These animals have invented everything you can possibly think of: light, electricity and so many bizarre lifestyles and shapes. And that's just the fish.

"The more you look through the Darwin Centre collection, the more wonderful things you find."