The fossilised remains of a 300m-year-old tropical forest are being shown at a museum near the site they were found.
It was uncovered during overcast mining works on the site of a former steelworks near Wrexham in 2003.
The forest in Brymbo pre-dated the dinosaurs and was from a time when what is now Wales was hot and humid and over the equator.
Geologists were excited at finding so many fossilised trees together. Now some are on show at Wrexham museum.
The From Coals to Carnations exhibition features a wide rage of fossils, with the oldest dating back several billion years, and Parkhill Estates Ltd have allowed some of the Brymbo fossil forest to be shown.
The Brymbo fossils date from the carboniferous period, before flowering plants.
Wales would have been dominated by tropical rainforests, whose compressed layers of decaying growth formed its coal deposits.
The "trees" were not like trees at all, but a giant club moss, which grew to a size of up to 40m.
There are three other fossilised forests in Scotland, Dorset and Sheffield.