We’ve all seen footage of the first men walking on the moon... but how exactly did they get there? This video details the fascinating, many-faceted construction of the Apollo 11 spacecraft so that we can see exactly what happened in what order to make this incredible journey a reality.

In part 2 about the borough of Manhattan, Sigrid completes her overview of all 5 boroughs of New York City. She talks about some nicknames for New York City, including "the Big Apple."

We've finally made it to Manhattan, the smallest but most densely populated borough. When we think of New York City, Manhattan is more often than not what comes to mind. This is part 1.

It's time to have a look at Staten Island, the 4th borough out of 5. It looks closer to New Jersey than to the rest of New York City and has some other peculiarities.

To get from eastern Long Island to the city, travelers and commuters have to go through Queens, so this borough naturally became a very important transit hub, with Jamaica at its center. It also became crisscrossed with many expressways for vehicles.

Having explored the Bronx and Brooklyn, Sigrid now tells us all about Queens, which is geographically speaking the largest of the 5 boroughs of New York City.

Autumn arrives, and the bison rut draws to an end. For many animals, this is a time of quiet preparations. They are getting ready for the hardships of another winter as the cycle of the seasons continues.

The height of summer brings striking rainbow colors to one of Yellowstone’s hot springs. This is also the peak of the bison rut, when the park’s muscular bulls challenge one another for the opportunity to mate.

This is a landscape in constant flux, with a live supervolcano simmering beneath the surface. But for the young animals, there is now time to relax and enjoy the warmth and tranquility of the late summer. As they move towards maturity, a mellow sunlight shines on peaceful scenes in Yellowstone National Park.

Color and new life returns to Yellowstone as summer returns, and the animals race to make the most of this window of warm weather, which they know will be as brief as it is bright.

Sigrid talks about the different ways to get from Brooklyn to Manhattan, and about some of the characteristics of this borough. For one thing, it is more affordable than Manhattan, although by no means a cheap place to live.

Without its pack, a wolf is a far lesser threat, and the other animals know it. However, for the lost bison calf, trapped on a small island, a lone wolf is a mortal danger, one that would take a minor miracle to survive.

In the first of two parts, we look at Brooklyn's beginnings and how it came to be one of New York City's boroughs.

A young bison calf is swept away by the icy torrent as the herd crosses a river. Against the odds, it washes up on a small island, but with night approaching, and its mother nowhere in sight, the outlook seems bleak for this little one.

The borough of the Bronx has gotten a bad name because of issues with poverty and crime. It's also had its share of neglect and mishandling on the part of local and state administrations. However, the Bronx also has some claims to fame, such as the Bronx zoo and botanical garden.