The library of the national palace of Maafra looks like the kind of library where something magical

could happen at any given moment. Think long hallways, bookshelves lining the walls all the way up

to these arched ceilings. It's an old library that's part of an old palace built in the 1700s

and its books are even older. There are more than 35,000 volumes here, including what's

considered the first encyclopedia, a whole collection of books that were forbidden during the

inquisition, and even in Canabula, books that were printed before the 16th century.

The collections here are extraordinarily rare, but the books aren't the only unusual things about

this library. At the end of the day, the lights are turned off, the building closes, and out come

the wind librarians of the night. I'm Abby Peralt, and this is Atlas Obscura, a daily celebration

of the world's strange, incredible, and wondrous places. Today, we're heading to Maafra,

Portugal, about 25 miles northwest of Lisbon, where we'll meet the library and who looks after

these books by day, and the bats that do so by night. After this.

For me, the library is all together the books. I have one that I left. It's about cartography. It's

from 16th century. That's Teresa Amaral. She's a librarian at the National Palace of Maafra.

I have lots of things to do, because it's not a normal library.

It's definitely not a normal library. It's a historical library, and maybe one of the most important

in Western Europe. And Teresa is kind of like the protector of this rare collection.

I have a big, big preparation about the conservation of the books.

A lot goes into protecting these volumes. Teresa and her team have to monitor the conditions

of the library to make sure the books don't crack or mold. I must know how is the temperature,

how is the humidity, every month. I go all over the library to see if there are any modifications

about humidity or temperature. And there's another part of caring for these super

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