0:00:07.015,0:00:09.485
When you think of natural history museums,

0:00:09.485,0:00:14.116
you probably picture exhibits [br]filled with ancient lifeless things,

0:00:14.116,0:00:15.435
like dinosaurs

0:00:15.435,0:00:16.463
meteroites,

0:00:16.463,0:00:17.867
and gemstones.

0:00:17.867,0:00:20.695
But behind that educational exterior,

0:00:20.695,0:00:25.032
which only includes [br]about 1% of a museum's collection,

0:00:25.032,0:00:29.558
there are hidden laboratories [br]where scientific breakthroughs are made.

0:00:29.558,0:00:31.196
Beyond the unmarked doors,

0:00:31.196,0:00:34.087
and on the floors [br]the elevators won't take you to,

0:00:34.087,0:00:37.488
you'd find windows into amazing worlds.

0:00:37.488,0:00:42.017
This maze of halls and laboratories [br]is a scientific sanctuary

0:00:42.017,0:00:45.744
that houses a seemingly [br]endless variety of specimens.

0:00:45.744,0:00:49.507
Here, researchers work to unravel [br]mysteries of evolution,

0:00:49.507,0:00:51.261
cosmic origins,

0:00:51.261,0:00:53.579
and the history of our planet.

0:00:53.579,0:00:57.013
One museum alone [br]may have millions of specimens.

0:00:57.013,0:01:00.103
The American Museum of Natural History[br]in New York City

0:01:00.103,0:01:04.079
has over 32,000,000 in its collection.

0:01:04.079,0:01:06.164
Let's take a look at just one of them.

0:01:06.164,0:01:09.478
Scientists have logged exactly[br]where and when it was found

0:01:09.478,0:01:14.035
and used various dating techniques [br]to pinpoint when it originated.

0:01:14.035,0:01:17.307
Repeat that a million times over,[br]and these plants,

0:01:17.307,0:01:18.371
animals,

0:01:18.371,0:01:19.228
minerals,

0:01:19.228,0:01:20.106
fossils,

0:01:20.106,0:01:25.239
and artifacts present windows [br]into times and places around the world

0:01:25.239,0:01:28.066
and across billions of years of history.

0:01:28.066,0:01:29.872
When a research problem emerges,

0:01:29.872,0:01:34.880
scientists peer through these windows[br]and test hypotheses about the past.

0:01:34.880,0:01:39.702
For example, in the 1950s, [br]populations of predatory birds,

0:01:39.702,0:01:41.331
like peregrine falcons,

0:01:41.331,0:01:42.393
owls,

0:01:42.393,0:01:45.014
and eagles started to mysteriously crash,

0:01:45.014,0:01:48.668
to the point where a number of species,[br]including the bald eagle,

0:01:48.668,0:01:50.929
were declared endangered.

0:01:50.929,0:01:54.553
Fortunately, scientists in [br]The Field Museum in Chicago

0:01:54.553,0:01:58.283
had been collecting the eggs [br]of these predatory birds for decades.

0:01:58.283,0:02:01.811
They discovered that the egg shells [br]used to be thicker

0:02:01.811,0:02:04.059
and had started to thin around the time

0:02:04.059,0:02:09.616
when an insecticide called DDT [br]started being sprayed on crops.

0:02:09.616,0:02:12.436
DDT worked very well to kill insects,

0:02:12.436,0:02:16.239
but when birds came and ate[br]those heaps of dead bugs,

0:02:16.239,0:02:19.372
the DDT accumulated in their bodies.

0:02:19.372,0:02:21.401
It worked its way up the food chain

0:02:21.401,0:02:26.473
and was absorbed by apex predator birds[br]in such high concentrations

0:02:26.473,0:02:28.299
that it thinned their eggs

0:02:28.299,0:02:32.086
so that they couldn't support [br]the nesting bird's weight.

0:02:32.086,0:02:33.669
There were omelettes everywhere

0:02:33.669,0:02:36.103
until scientists from [br]The Field Museum in Chicago,

0:02:36.103,0:02:37.642
and other institutions,

0:02:37.642,0:02:40.493
helped solve the mystery and save the day.

0:02:40.493,0:02:42.778
America thanks you, Field Museum.

0:02:42.778,0:02:45.341
Natural history museums [br]windows into the past

0:02:45.341,0:02:48.326
have solved many other [br]scientific mysteries.

0:02:48.326,0:02:50.706
Museum scientists have used [br]their collections

0:02:50.706,0:02:53.077
to sequence the Neanderthal genome,

0:02:53.077,0:02:56.129
discover genes that gave mammoths red fur,

0:02:56.129,0:03:01.176
and even pinpoint where [br]ancient giant sharks gave birth.

0:03:01.176,0:03:04.476
There are about 900 [br]natural history museums in the world,

0:03:04.476,0:03:07.306
and every year they make [br]new discoveries and insights

0:03:07.306,0:03:10.934
into the Earth's past, present and future.

0:03:10.934,0:03:14.208
Museum collections even help us [br]understand how modern threats,

0:03:14.208,0:03:16.172
such as global climate change,

0:03:16.172,0:03:17.861
are impacting our world.

0:03:17.861,0:03:20.404
For instance, [br]naturalists have been collecting samples

0:03:20.404,0:03:24.029
for over 100 years from Walden Pond,

0:03:24.029,0:03:27.139
famously immortalized [br]by Henry David Thoreau.

0:03:27.139,0:03:30.426
Thanks to those naturalists,[br]who count Thoreau among their number,

0:03:30.426,0:03:32.735
we know that the plants around Walden Pond

0:03:32.735,0:03:38.132
are blooming over three weeks earlier [br]than they did 150 years ago.

0:03:38.132,0:03:40.566
Because these changes [br]have taken place gradually,

0:03:40.566,0:03:44.710
one person may not have noticed them[br]over the span of a few decades,

0:03:44.710,0:03:46.635
but thanks to museum collections,

0:03:46.635,0:03:51.535
we have an uninterrupted record [br]showing how our world is changing.

0:03:51.535,0:03:54.375
So the next time you're exploring [br]a natural history museum,

0:03:54.375,0:03:57.361
remember that what you're seeing [br]is just one gem

0:03:57.361,0:04:00.716
of a colossal scientific treasure trove.

0:04:00.716,0:04:05.448
Behind those walls and under your feet[br]are windows into forgotten worlds.

0:04:05.448,0:04:06.609
And who knows?

0:04:06.609,0:04:11.697
One day some future scientist may [br]peer through one and see you.