- Gilbert?

Are you coming to the cavern too?

- Ab-so-tootly-lutely, Miss Shiny.

I wouldn't miss it.

- All right, then.

I like this idea.

[ting] - Can we show them where we're going, Uncle Conductor?

- Well, we could show it to 'em, but I'd rather sing it to 'em.

Oh, yeah.

- Whee!

- Whoo-hoo!

- ♪ We've been up ♪ ♪ We've been down ♪ ♪ Here and there, all around ♪ both: ♪ But this time the train's going underground ♪ - [gulps] - ♪ Deep down under the Earth's foundation ♪ ♪ There's a place called Cretaceous Cavern Station ♪ - ♪ But, my friends, that's just the start ♪ ♪ We're digging down to a deeper part ♪ ♪ We'll dig as deep as we can handle ♪ ♪ Maybe all the way till we reach the mantle ♪ - ♪ We'll probably stop there, it's pretty hot there ♪ all: ♪ What's at the center of the Earth?

♪ both: ♪ Who knows what we'll discover?

♪ all: ♪ What's at the center of the Earth?

♪ both: ♪ Who knows what we'll uncover?

♪ - ♪ Caverns ♪ - ♪ Rivers ♪ - ♪ Jewels and minerals ♪ - ♪ But I hope not red-hot lava ♪ all: ♪ What's at the center of the Earth?

♪ ♪ ♪ - ♪ I'm so glad we're on this ride ♪ ♪ Who knows what's on the Earth's inside?

♪ - ♪ Can we dig right through ♪ ♪ And come out the other side?

♪ - ♪ A fun thought, Don ♪ ♪ But probably not, Don ♪ - Aw.

all: ♪ What's at the center of the Earth?

♪ ♪ ♪ ♪ What's at the center of the Earth?

♪ [all cheering]