gistfile1.php

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

$c->find( [
    'loc' => [
        '$geoWithin' => [
            'type' => 'Polygon',
            'coordinates' => [ [
                [ -0.91, 51.74 ],
                [ -0.91, 51.27 ],
                [  0.67, 51.27 ],
                [  0.67, 51.74 ],
                [ -0.91, 51.74 ]
            ] ],
            'crs' => [
                'type' => 'name',
                'properties' => [
                    'name' => 'urn:x-mongodb:crs:strictwinding:EPSG:4326'
                ]
            ]
        ]
    ]
] );
?>