How can I make PHP display the error instead of giving me 500 Internal Server Error

Check the error_reporting, display_errors and display_startup_errors settings in your php.ini file. They should be set to E_ALL and "On" respectively (though you should not use display_errors on a production server, so disable this and use log_errors instead if/when you deploy it). You can also change these settings (except display_startup_errors) at the very beginning of your script to set them at runtime (though you may not catch all errors this way):

error_reporting(E_ALL);
ini_set('display_errors', 'On');

After that, restart server.

Use "php -l <filename>" (that's an 'L') from the command line to output the syntax error that could be causing PHP to throw the status 500 error. It'll output something like:

PHP Parse error: syntax error, unexpected '}' in <filename> on line 18

It's worth noting that if your error is due to .htaccess, for example a missing rewrite_module, you'll still see the 500 internal server error.