- [David] London.

Nine million people, two and a half million cars, and miles of concrete, tarmac, and steel.

- Good evening, sir.

Where to?

- Richmond, please.

- [Driver] Richmond it is.

- But there is a wild side to London.

The desire to bring your natural world back into our cities is gaining momentum.

Now we can recognize you anywhere.

Yes, you.

Life in London clearly suits them very well indeed.

Tonight, he's searching for a mate.

There they are.

Wild beavers in London.

Hello.

It's still a huge thrill to see a totally wild creature.

When it comes to discovering the wonders of nature... - Mind the door.

- There really is no place like home.

(wings flapping) - [Martin] What happens here is something I've been waiting to film for much of my life.

- [Narrator] Above flat, muddy waters, a natural wonder unfolds.

- [Martin] It's kind of like an empty stage waiting for the players to arrive.

- [Narrator] The players are seabirds in the thousands.

- [Martin] There is a well-rehearsed choreography at work here.

Right in the heart, there's one bird, a conductor, that's driving everything.

- [Narrator] It's a dance between an army of prey and a single predator, the peregrine falcon.

- It's this incredibly rich, complex drama laid out on a huge stage, two miles across, a mile high.

The air is just thick with birds.

It's a cosmic spectacle.

- [Radio] She's up the road, Dan.

She's on the road.

(tiger growls) - I can see her.

I can see her.

She's really close.

It's incredible.

She was so close to me.

(exhales) I'm shaking.

- [Narrator] Tigers are secretive and hard to track, but here on an open island in Nepal, their lives can be filmed from the air.

(tiger growls) Follow a team of wildlife experts as they utilize the latest technology to track three tiger moms.

- One of the cubs just rocked up with something fluffy in its mouth.

- [Narrator] Day and night.

- [Researcher] She's looking right at us.

Just stay dead still.

- [Narrator] The trials of motherhood will unfold.

- [Researcher] She's trying to keep him away from her cubs.

- [Narrator] Along with the challenges of filming wild animals.

- I think we need to back away.

This is actually a slightly dangerous situation.

- [Narrator] There's nowhere better in the world to observe tiger behavior.

- Tigers are so much more complex, more social than we ever thought possible.