On 25 January 1938 (during solar cycle 17), bright lights, an aurora borealis appeared over the northern hemisphere, including in places as far south as North Africa, Bermuda and California. It was the widest occurrence of the aurora since 1709 and people in Paris and elsewhere believed a great fire was burning and notified fire departments. Sister Lúcia indicated that it was the sign foretold and so apprised her superior and the bishop in letters the following day. Just over a month later, Hitler seized Austria and eight months later invaded Czechoslovakia.