Zmarzły Staw Gąsienicowy — literally 'the Frozen Tarn of the Gąsienica Valley' — is one of the most remote and atmospheric mountain lakes in the Tatra Mountains. Nestled at 1788 m above sea level in a rocky cirque beneath the walls of Mały Kozi Wierch, it feels like a place truly left to the wilderness. In 1865, Polish writer Michał Bałucki described it as 'perhaps the wildest retreat in the Tatras'.

The lake is small — just 77 m long and 50 m wide — but its setting is breathtaking. Hemmed in by rock walls and sitting at the mouth of the Dolinka Kozią valley, it stays frozen for most of the year, typically thawing only in June or July and freezing again in September or October. In winter it freezes solid to the bottom. When it finally melts, the dark, still water reflects the surrounding crags in a scene that has inspired painters like Wojciech Gerson and Stanisław Witkiewicz, as well as several Polish poets. The atmosphere here is one of profound solitude and raw mountain beauty.

• From the trail junction above Czarny Staw Gąsienicowy — trail towards Kozia Przełęcz, approx. 1 h up (50 min down), moderate difficulty.

• Access is seasonal — the trail may be impassable outside of summer due to snow and ice.
• Rare protected plant species grow around the lake, including Saussurea alpina and stiff sedge. Stay on the marked trail.
• Just above the lake, near the trail to Kozia Przełęcz, there are traditional shepherd shelters ('koleby').

A small stream drains the tarn downhill to the larger Czarny Staw Gąsienicowy — making this a rewarding extension to an already beautiful valley walk.