The slanted limestone layers of the meteor crater near Kärdla, Hiiumaa island put pressure on groundwater. The water bursts out of the ground in an uninterrupted stream through pipes placed 10–15 metres under the ground's surface.
There are especially many artesian wells on Tiigi and Aia streets and people can also drink crystal-clear water from the well on the corner of Aia and Pikk streets. You will see many fountains in the yards when walking down Aia Street – these are all artesian.
They look especially beautiful in winter when ice sculptures form on the fountains.