CHICAGO (CBS) — Hundreds of young climate protesters are planning took over parts of downtown Chicago during evening rush hour Monday.

The protesters demanded the city declare a climate emergency.

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They made their way from Trump Tower to City Hall after chanting and holding signs at Daley Plaza.

Outside City Hall, protesters did something they called a “young only die-in.” They lay on the steps for 11 minutes as they called for the climate emergency.

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Some climate experts believe the world has just 11 years to make changes before the damage to the climate is irreversible.

The protesters had hoped they would be joined by Greta Thunberg, the Swedish 16-year-old environmental activist quickly becoming one of the biggest voices for climate change. But Thunberg was not able to attend.

The teen was in Chicago Thursday and posed for a picture in front of Buckingham Fountain. The next day she was in Iowa at a rally where it looked like hundreds came out.

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More than 30 Chicago area groups are coming together for the event Monday.