The history of the resort house «Sonyachna Dolyna» (Sun Valley) begins with mineral water «Polyana Kvasova» (Kvasova Polyana). This water is more than 500 years old. The first mentions about it are found in the muniments of the Hungarian king dated by 1463. Among natural healing table waters of Ukraine «Polyana Kvasova» is one of the most popular ones. One of the springs of Polyansky mineral water deposit, which is 2 km away from the center of Polyana village, has brought Poliansky kvasova waters a great fame. As it is commonly known, in Transcarpathia the springs were called 'Burkuts' and mineral water - kvasova water, or kvass. Initially, the water from these springs was exported by barrels, but already in 1840, it was bottled and exported to various countries of Europe under the name "Polyanska".

In 1914, an illustrated guide to the resorts and mineral springs published by Balneotherapeutic Society of the Holy Crown of Hungary described the Polyana spring, as "first class water, splendid table water, which, mixed with milk, is an excellent means of mucus dissolving. So far, only facilities for bottling and packaging of mineral water are found in this place. However, the superb location of the spring, wonderful air, climate and area that is protected from all sides by mountains can be used as a resort".

"For the healthy this is a beverage with wonderful taste, quenching one`s thirst mixed with wine, cognac or citric acid" (advertisement, 1913). Mineral water Polyanska had been marked in: Budapest 1842, Paris 1855, Vienna 1866, 1873, Budapest 1882, 1883, Kosice 1880, Vienna 1884, Budapest 1884, Sobrance 1881, Uzhgorod, 1883, Maramorosh-Sziget 1882, Budapest 1885, 1895, 1911.

Diplomas and Rewards: Vienna 1873, 1894, Budapest 1885, 1896 (Millennium), Chernivtsi 1886, Luhosh 1911.

Chemical composition of mineral water had been studied by university professors in Budapest; as well as by doctors, chemists, pharmacists of Austria, Hungary, and Czechoslovakia. According to these studies in the springs of Polyana deposit in addition to a high content of hydrocarbons, the presence of boron, iron, and lithium was revealed.

Resuming the bottling of Polyana mineral water under the name «Polyana Kvasova» started in 1946, this time, from the bore of an eastern part of New-Polyana area of a Polyana deposit, at the factory for bottling mineral water «Polyana Kvasova» (at the location of former factory) and Svaliava mineral water plant. Mineral water is being distributed in Ukraine and is exported to the CIS countries, USA and Canada.

In 1965, based on the mineral water «Polyana Kvasova» from the bores drilled in the western part of New-Polyana area deposits, on the left bank of the river V.Pynya near the stream 'Nameless', between the ridges of the Ukrainian Carpathians, at an altitude of 340m above the sea level, there appeared a resort «Sonyachne Zakarpattya» (Sunshine Transcarpathia). In 2002, on the territory of this resort the first stone was laid for the construction of a resort house «Sonyachna Dolyna», and in 2005 the resort started functioning. To have a rest in this resort house people started to come not only from Ukraine but also from countries near and far abroad. The surrounding mountain scenery, forests and temperate continental climate have always enhanced the first-class recreation. Multiformity, an unusual beauty and richness of nature in this region is due to the fact that the resort "Sonyachna Dolyna" is on the verge of the mountain and foothill areas, surrounded by a relatively easily accessible mountains covered with forest. It is protected from cold winds by the mountains on the north, west, and east, and is open to the south. This preconditions a clean, clear, rich with phytoncides and light air-ions healing air.

The most famous ancient Greek physician and naturalist Galen wrote, "Nature is the best doctor". In addition, an excellent complement to medical treatment became the diagnostic center «Sonyachna Dolyna», which started functioning in 2006, with the following divisions: balneology, physiotherapy, laboratory, pneumatotherapy, and massage rooms. The acidulous hydrocarbonate-sodium water "Polyana Kvasova" became the main remedy, which is widely used in the health centre «Sonyachna Dolyna» pumprooms, as well as in mineral baths, intestinal lavage, inhalations, and other procedures. Thanks to its remarkable antacid and buffer properties, mineral water «Polyana Kvasova» is the most powerful in treatment of all stomach diseases with an increased level of acidity, reflux-esophagitis, concomitant changes in a hole- and pancreatostasis and chronic pancreatitis, hepatose, hepatitis, diabetes. Gradually, therapeutic and diagnostic facilities of the resort grew.

Thus, in 2007 the oxygen therapy was introduced, together with ozone therapy.

In 2008, SPA-division started functioning; also, introduction of cosmetic procedures, alternative medicine, and stone therapy took place. This year lymphatic drainage started to be used.

Year 2009 is the year of launching and development of endocrinological, cardiological, neurological, gynecological, urological treatment areas. In 2011, the laboratory and ultrasound equipment was renovated for more modern, with greater capacity for performance of more advanced tests, a new technology of videocapsular endoscopy was introduced, halochamber was opened (the salt cave) with the introduction of speleotherapy.

In the course of functioning of the treatment and diagnostic center «Sonyachna Dolyna», hundreds of people underwent an examination and treatment complex. For dozens of them many different diseases were promptly detected and prevented. However, not only bodily, but also spiritual health was improved and supported for thousands of people, who took a treatment course in «Sonyachna Dolyna». During a relatively short period of «Sonyachna Dolyna» functioning, it was on numerous occasions awarded with diplomas of village, district and regional administrations.

For the day, «Sonyachna Dolyna» keeps on pleasing its guests with comfort and professional approach of the staff to their work.