A small pavilion in the style of a classical “temple” with an octagonal ground plan, penetrated by large windows and roofed by a dome with a lantern originally stood above the source of Buková kyselka (“Beech acidulous water”). In the late 1820s, it was replaced by an Empire-style gloriette with a circular ground plan (several such gloriettes are known from this period from nearby Karlovy Vary). Tuscan order columns supported a low dome with an open tambour and a free spherical cap. After the visit of King Otto of Greece in 1852, when the spring received its name in honour of the royal guest, the construction of a new wooden colonnade to be designed by builder Bernhard Grueber commenced. The ceremonial opening of the colonnade took place on 23 September 1853. In 1862, a new spa house in the English romantic and Neo-Gothic styles was built to the left of the colonnade, also apparently based on Grueber’s design.
Between 1897 and 1898, a new colonnade and pavilion for Otto’s Spring were built in the place of the wooden colonnade based on the design of architect Karl Haybäck from Vienna. The Otto’s Spring pavilion itself is a central structure with a square ground plan and bevelled corners forming the interior octagonal layout, roofed with a majestic dome. A grandiose scene featuring Neo-Baroque décor with marble tiling (stucco lustro) in colour combinations of red, grey and light marble, with gilded band motifs, Baroque-evoking cartouches, laurel wreaths and the initials HM monograms unfolded inside the pavilion. Lofty stained-glass panes were fitted in the cupola. The architectural expression emphasises the sumptuousness and significance of the building, with Neo-Baroque pomp going hand in hand with Art Nouveau stylisation. The Mattoni eagle with Heinrich Mattoni’s coat of arms looks down upon us from the attic gables. In connection with the new collection of Otto’s Spring, the pavilion was extended and an annexe, with the same architectural expression as the colonnade adjoining from the other side, was added to the southern gable of the pavilion in 1910. A funicular railway used for taking crates of empty bottles up and bringing them back down for shipping after they had been refilled in the Otto’s Spring bottling plant, led up the slope from Jindřichův dvůr (Henry’s Court) to the top of the elevation. The plateau in front of the colonnade and pavilion was enclosed by a balustrade with a ceremonial direct staircase.