protected function rebuildTitles()
    {
        // Update the Title field in the dataobjects. This saves the time to build the title dynamically each time.
        foreach (TimeZoneData::get() as $tz) {
            $newTitle = $tz->prepareTitle();
            if ($newTitle != $tz->Title) {
                $tz->Title = $newTitle;
                $tz->write();
            }
        }
    }