Watch: When US Commander-in-Chief Barack Obama forgot to salute a Marine

Nothing gets really old on the internet. Things come and go and come back again. The same is happening with a two-year-old video of US president Barack Obama showing him forgetting to salute a US Marine as he boards the helicopter, Marine One.

US President Barack Obama was on his way to Annapolis, Maryland and looking at the video, seemed pre-occupied. He did not salute the Marine standing at the bottom and boarded the helicopter. 

But Obama quickly realised the faux pas and came down to shake hands with the Marine and spoke with him before quickly returning to the helicopter.

It is a longstanding tradition in the US that military personnel are required to salute the president as a sign of respect. In 1981, US president Ronald Reagan started the tradition of returning the salute.