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 ]
                ] ],
                'crs' => [
                    'type' => 'name',
                    'properties' => [
                        'name' => 'urn:x-mongodb:crs:strictwinding:EPSG:4326'
                    ]
                ]
            ]
        ]
    ]
] );
?>