A June heat wave in Belgium and neighboring countries exposed a lethal lack of readiness. That’s a risk as another wave hits Europe.

© Ksenia Kuleshova for The New York Times

A June heat wave in Belgium and neighboring countries exposed a lethal lack of readiness. That’s a risk as another wave hits Europe.

© Ksenia Kuleshova for The New York Times

The biometric system for non-E.U. citizens is causing long delays and short tempers at airports. Officials say the rocky rollout will get better and will improve security.

© Armando Franca/Associated Press