Anita Rani, Ade Adepitan, Ant Anstead and Dan Snow are in New York's Central Park.

From their base, they reveal the hidden systems and organisational miracles that keep the world's busiest urban park clean and green.

Ade heads to Harlem and meets residents who are benefiting and suffering at the hands of gentrification. Meanwhile, Ant is at Hudson Yards on the west side of Manhattan where an entirely new district is being built on top of a functioning rail depot - an innovative building solution to the island's lack of land.

Historian Dan Snow is in Coney Island discovering that television, air conditioning and extreme weather almost killed off this historic amusement zone. And viewers are taken inside a multi million dollar penthouse apartment - accompanied by an estate agent who holds the record for selling New York's most expensive house.