The army's seizure of power halted the Southeast Asian nation's move toward democracy that began when Suu Kyi's party took office in 2016 for its first term, after more than five decades of military rule.
Witnesses outside Insein Prison in Yangon on Wednesday saw busloads of mostly young people, looking happy with some flashing the three-finger gesture of defiance.
Myanmar has been roiled by protests, strikes and other acts of civil disobedience since the coup toppled Suu Kyi's government on February 1 just as it was to start its second term.
Bagan is best known for being one of the country's top tourist attractions, but it has also been the scene of large protest marches against the military's February 1 seizure of power.