Obama last visit to Athens as a US President

US President Barack Obama on his first Athens as he wave the world goodbye as the United State president, Obama stressed that European was "good for the world and the US"
but it have been shaken after Trump appeared to call into question Washington's near 70 years security guarantee saying that he would only help NATO allies if they paid their way.  

Obama said "Across Democratic and republican administrations there is a recognition that the NATO alliance is absolutely vital"

"I'm certain that he will be a president , who will live up to all the commitments of the United States alliance, because NATO is important for Europe but it's also important for the United States"  Said NATO head Jeans Stoltenberg.