gistfile1.php

<?php
$c = (new MongoClient())->demo->points;

$c->find( [
    'loc' => [
        '$geoWithin' => [
            '$geometry' => [
                'type' => 'Polygon',
                'coordinates' => [ [
                    [ -0.91, 51.74 ],
                    [ -0.91, 51.27 ],
                    [  0.67, 51.27 ],
                    [  0.67, 51.74 ],
                    [ -0.91, 51.74 ]
                ] ]
            ]
        ]
    ]
] );
?>