Override Google Maps API call URI and add Google Maps API Key

functions.php

<?php
/**
 * The Events Calendar: Override Google Maps API call URI, such as to include
 * additional libraries (e.g. drawing, geometry, places, visualization).
 *
 * @link https://gist.github.com/cliffordp/9d6c25feb389f98e8ae09a41273a3488
 * @link https://developers.google.com/maps/documentation/javascript/libraries
 *
 * @see add_query_arg()
 * @see esc_url_raw()
 **/
add_filter( 'tribe_events_google_maps_api', 'cliff_tec_modify_google_maps_uri' );
add_filter( 'tribe_events_pro_google_maps_api', 'cliff_tec_modify_google_maps_uri' );
function cliff_tec_modify_google_maps_uri( $api_url ) {
	$api_url = add_query_arg( 'libraries', 'drawing,geometry,places,visualization', $api_url );

	// esc_url() will break it so esc_url_raw() or don't escape at all
	return esc_url_raw( $api_url );
}