An Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)

An Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)

An Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)

The surrounding roads are closed as an Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)

An Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)

An Extinction Rebellion protester demonstrates on the scaffolding surrounding the Elizabeth Tower, also known as the Big Ben, in London, Britain, on Oct. 18, 2019. (Photo by Stephen Chung/Xinhua)