Military organisers estimated that 70,000 people attended a 'Meet the Forces' day in Cardiff Bay on Sunday, at the end of the Nato summit Wales week.
Police have hailed the security operation - the largest the UK has ever seen - as a success, with 31 arrests made in total.
World leaders including Barack Obama left Wales on Friday, praising Newport and Cardiff for a warm welcome.
Parents and pupils across South Wales have spoken of their frustration at school closures later this week due to the NATO summit in Newport.
More than 160 schools will be closed, or open for reduced hours, between Wednesday and Friday - primarily due to concerns over whether staff will be able to travel in.
Read More: How schools will be affected in your area
Parents and pupils, many of them returning to school today after the summer holidays, say being forced to have more days off will disrupt learning, and make it difficult for many to balance work and the school run.
Tom Sheldrick reports:
Top policeman at Nato Summit says stun grenades were destroyed an hour before they were set to explode in path of world leaders.
'Meet the Forces' day was a crowd puller on Sunday as warships open up their decks in Cardiff Bay following Nato summit.
The day began with a spectacular fly-past over Cardiff and Newport by Nato aircraft.