Authorities in Europe have ramped up counterterrorism efforts, making hundreds of arrests. Dutch police in November arrested members of the Hofstad Islamist group.

A sliver of good news from across the Atlantic: things could be much worse. Since the 2004 bombings in Madrid, authorities across the Continent have ramped up counterterrorism efforts, making hundreds of arrests and foiling several large-scale plots. Here’s a rundown of some notable successes.

1) BRITAIN

British authorities charged…