At the height of his popularity, the artist realised the outdoor sculpture 'Burning Pieta' in Denmark at Museum Louisiana in 1972. He then went to Sweden, where he already had several friends and was increasingly highly regarded. For some years now, he had been experimenting with earth forms, cement casts in the ground, and flaming sculptures.

"Solidified in the ground, spanned by iron bones, concrete is the challenge of a sculptor who, in his volcanic extravagance, has once again longed for ascetic, unambiguous expression. The Sebastian series, which forms a multi-faceted monument to the memory of hostages shot in Nowy Sącz, represents Polish art at the First Biennale of Outdoor Sculpture in Montevideo in 1969, and burns 'Against the War' in front of the Polish pavilion at the XXXV Venice Biennale. Using the same technique Hasior then realises the sculpture "Burning Pieta" in Denmark, he lets loose a frisky herd of horses of "Sunny Chariot" in Södertalje near Stockholm."

(Anna Micińska, 1977)

Hasior himself recalled that the director of the cultural centre in Södertalje, Eje Hogestatt initially wanted to commission a group just modelled on the monument to the executed. "I declined, presenting another, old idea: the horse-Pegasus. (...) They 'run' along a hillock overgrown with pine trees, over the canal by which ships enter the harbour. They are visible from a distance: from the side they are silver-white, from the land they are red-brown. I made them like the previous monumental compositions - in the ground, with reinforced cement. I even managed to solve the problem of their risky statics myself (...) The composition is bound together by this 'solar chariot', drawn with a line of white cement on the hillside. I was inspired here by drawings from the Viking Age that still mysteriously decorate the great rock boulders of Scandinavia" (statement from 1974). This last component of the group has not survived, nor has the original colouring of the figures and the concrete dome about 1 m in diameter, symbolising the sun. The group of eight horse figures are spaced a few metres or so apart on the slope, each figure measuring up to 7 m long, the tallest being 8 m high.

The sculptures have troughs on their backs, intended for a flammable substance - used during fire actions (such evenings with poetry were held in June in the 1970s, the last one in 1986 on the 10th anniversary of the group's inauguration).