public function toArray()
    {
        $list = [];

        // Add popular timezones to list
        foreach ($this->popularTimezones as $key => $value) {
            $list['General'][$key] = $value;
        }

        // Add all timezone of continents to list
        foreach ($this->continents as $continent => $mask) {
            $timezones = DateTimeZone::listIdentifiers($mask);
            foreach ($timezones as $timezone) {
                $list[$continent][$timezone] = $this->formatTimezone($timezone, $continent);
            }
        }

        return $list;
    }