Freed Austrian dungeon boys Stefan and Felix Fritzl have taken their first ever steps in the outside world.

The brothers, raised by their mother Elisabeth in a dungeon under the home of her cruel dad Josef Fritzl, finally ventured out of the psychiatric clinic where they are recovering from their ordeal.

And they marvelled at their surroundings as they wandered among trees, picked flowers and gazed at wildlife.

They were especially fascinated by hundreds of goldfish swimming in a pond in the grounds of Austria's Mauer Landesklinkum clinic.

Stefan, 18, his five-year-old brother and Elisabeth, 42, have now discarded the protective goggles doctors insisted they wear as their eyes adjusted to sunlight.

The boys have been given the immunisation jabs normally received by newborn babies, but which their mother was unable to provide during years of incarceration at their subterranean home in Amstetten.

Doctors were concerned that the boys lacked immunisation to everyday illnesses but after their innoculations were believed to have enough resistance to mix with other people.

Sources said the pair, who first saw daylight as they were plucked from the cellar last month, enjoyed their first walk outside.

Their mother Elisabeth was held captive underground for 24 years by her father, Josef, 73, and had seven children by him, one dying as a baby.

She is learning to bond again at the clinic with her other children, Lisa, 16, Monika, 14, and Alexander, 12, who were all allowed an existence above ground.

She is also living with her own mother, Rosemarie, Josef's 69-year-old wife.

Hospital sources have said: "Elisabeth and Rosemarie enjoy cooking for the children and giving them new tastes. Stomaching new foods is no problem for Stefan and Felix. They are fascinated by every dish. The youngsters are allowed DVDs and computer games at night. The siblings have gelled incredibly well. It's astounding to think how quickly they have all slotted into their new family roles."