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.
Gwent Police and Crime Commissioner Ian Johnston is welcoming the announcement the Celtic Manor Resort near Newport will host next year's NATO summit:
“.... (the) announcement is positive and welcome news for Gwent and the whole of South Wales. The size, scale and importance of the event cannot be over estimated, and policing and security will need to be of the highest standard"
Gwent Police Chief Constable Jeff Farrar says:
"This is a great opportunity for Gwent to once again showcase itself on an international stage, and we are delighted to be welcoming such a prestigious event to our policing area.
“It will be an enormous challenge for the Force but with our track record of having policed the 2005 European Union Foreign Ministers summit and the 2010 Ryder Cup at the same venue we are confident that working with other agencies and partners the event will be both safe and secure."
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.