- simplexml_load_string: documentation ( source)
<?php
$xml = "<root>
<URL>https://pdt.multimediarepository.testing.amadeus.com/cmr/retrieve/hotel/0404104C5B6E42CCAFE3E7F3083F6666/A</URL><URL>https://pdt.multimediarepository.testing.amadeus.com/cmr/retrieve/hotel/0404104C5B6E42CCAFE3E7F3083F6666/B</URL>";
$xml = simplexml_load_string( $xml);
foreach( $xml->xpath( './/URL') as $child) {
echo $child . "\n";
}