Donald Trump and his wife Melania breached protocol when they greeted the Queen at her Windsor Castle: the American president failed to bow while the first lady did not curtsy. Instead, they simply shaking hands, Daily Mail report.
Mr Trump’s motorcade swept along the gravel drive and stopped at a dais where the Queen greeted the American leader and his wife after they stepped from the vehicle.

The Trumps’ greeting – seen by millions on television worldwide – was in contrast with Theresa May’s deep curtsy last month when she greeted Prince William at an event in Nottinghamshire. The prime minister performed a strikingly low dip as she shook the Duke of Cambridge’s hand.
A royal family spokesperson said while the general courtesy was to “curtsy or bow” before a member of the royal family, particularly the Queen, this was completely down to “personal choice”.
“For men this is a neck bow (from the head only) whilst women do a small curtsy. Other people prefer simply to shake hands in the usual way,”
the Palace’s website says.