The answer is: The mountains

Mark 13:14

In the Gospel of Mark, when Jesus mentions that those in Judea should flee to the mountains upon witnessing "the abomination of desolation" (Mark 13:14), He is gearing up to address a remarkable yet distressing prophecy. This phrase, "abomination of desolation," has intriguing roots in the Book of Daniel, where it referred to desecrating acts in sacred places. In Mark's context, it's a strong warning to prepare for impending disaster, lurking behind the scenes of impending events in the Holy City.

Fun fact: Many scholars believe this prophecy forewarned the Jewish War against the Romans, which was a catastrophic episode culminated by the destruction of the Second Temple in 70 CE. The reader is transported to a time when restless waves of political unrest and increasing oppression were sweeping through Jerusalem.

Thinking about the imagery of "mountains" serves as a vivid metaphor. If the Jerusalem populace were to flee, those rugged heights would symbolize safety and refuge—much like the faithful seeking solace in the tents of David, or similarly referenced locations throughout scripture where God's presence would create hope and shelter in chaos.

Moreover, Jesus connects these words with the urgency of preparedness, reminding listeners not only of historical events but of spiritual vigilance as well. In our modern world, where chaos pervades, we too might consider our own "mountains"—those personal and spiritual refuges that offer places of safety, hope, and tranquility amidst the storms of life. It's a call to genuine mindfulness during tumultuous times.