Underground Underground
WONDERS! WONDERS!
Tunnel Trains
To solve traffic problems, many big
cities have underground railways called
subways. Subway trains carry people
all over the city through tunnels. The
London Underground is a subway
system in England. It was opened in
1863 and is the oldest subway
in the world. It carries
over 5 million people
through London
every day!
The ground beneath our feet is not
just dirt and worms! There are lots of mind-boggling
natural and human-made wonders to discover.
Let's dig in.
The London Underground's
nickname is the Tube.
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