<?php

$string = '<a href="google.com/maps">Go to google maps</a> and some special characters ë è & ä etc.';

$string = htmlentities($string, ENT_QUOTES, 'UTF-8');

$doc = new DOMDocument('1.0', 'UTF-8');
$doc->preserveWhiteSpace = false;
$doc->formatOutput = true;

$root = $doc->createElement('top');
$root = $doc->appendChild($root);

$title = $doc->createElement('title', $string);
$title = $root->appendChild($title);

$id = $doc->createAttribute('id');
$id->value = '1';
$text = $title->appendChild($id);

$text = $title->appendChild($text);

$doc->save('data.xml');

echo 'data saved!';
?>