LONDON — Parry Malm and Shannon Wiseman weren’t expecting a “pivotal moment” in their sons’ lives when they visited Scotland’s Loch Ness earlier this month, but that’s exactly what happened.

“Our youngest is turning three next week,” said Wiseman from the family’s home in London, England. “And he tells everyone there have been two pivotal moments in his life: Seeing the world’s largest dinosaur, which he did at the Natural History Museum in January, and seeing Nessie.