<?php
$rawTz = "Lisbon";
foreach (DateTimeZone::listIdentifiers() as $timezone) {
            //echo $timezone;
            
            if(preg_match("/.*?\/$rawTz/", $timezone)){
            	echo $timezone;
            }
        }
        
        
//echo array_search('New_York', DateTimeZone::listIdentifiers(), true);
//print_r(preg_grep ( '/.*?New_York.*?/i' , DateTimeZone::listIdentifiers()));