This magical tunnel is located in the town of Kleven, near to the Ukranian border in Poland, and it has around 3 km of extension, completely covered by vegetation. The tunnel is actually a railway path and connects the town to a furniture factory, and three trains pass there per day, carrying wood to the factory.

They called it the tunnel of love because of an old tale the locals used to say: if a couple passes through the tunnel hand by hand, their love will last forever!!  

How to visit:

First of all, you should put some mosquito repellent because there are many of them in this area.The best time to visit it should be gone - September, to see that mystic green you're looking for. In spring/autumn the forest will be more colorful with browns and yellows.You can go your own with public transportation from the Lutsk or Lviv towns, and there's no entrance fee to enter the tunnel. 

If you're more like a tour kind of person, you have this ones:

https://www.viator.com/searchResults/all?text=tunel%20of%20love&destId=22377

Happy journeys in Ukraine!