This video is called Glow worm(s) (Lampyris noctiluca) part 3. Southern Finland.
From Wildlife Extra:
Where to see Glow worms in the UK
Female glow-worms produce a soft light in their tails during early summer nights to attract males.
But the romance is a rushed one – adult beetles survive for just a few weeks and in that time they need to mate and lay eggs to ensure the survival of the next generation.
Once far more widespread than they are today, glow-worms have cast a spell over humans for centuries. Shakespeare mentions them in Hamlet and their soft glow on mid-summer nights must have seemed like a scene from a magical world.
Where & when to see glow worms in the UK
Glow worms are nature’s nightlights and are at their best in July. Some of the UK’s best spots to see them are:
14 fun facts about fireflies: here.
MEDFORD/SOMERVILLE, Mass. (June 25, 2012) – The twinkling of fireflies heralds summer romance for these magical insects. While courting on-the-wing, male fireflies attract females’ attention with bioluminescent flashes: here.