Extinction Rebellion activists have held an "opening ceremony" ahead of twoweeks of planned protests across London.The environmental group plans to shut down key sites, including Westminsterand Lambeth bridges, in addition to protests outside key governmentdepartments.More than a thousand people attended an "opening ceremony" at Marble Arch onSunday evening, featuring meditation and dancing as "inspiration" prior to theprotests.Groups of artists held a procession around Marble Arch as the ...