Hvížďalka, Natural monument and protected area in Prague, Czech Republic.

Hvížďalka is a natural monument in Prague protecting a reference geological section of the Ludlow–Přídolí boundary, a comparison profile for the international stratotype of that boundary in the Czech Republic. The site is also a fossil locality.

Hvížďalka is a reference section for the Ludlow–Přídolí boundary, the level used to compare this horizon with the international stratotype. The Czech Republic protects it as a natural monument, ev. no. 1111, managed by AOPK ČR through the Český kras administration. The site is also a fossil locality.

Hvížďalka is a reference section for the Ludlow–Přídolí boundary, a supplement to the international stratotype of that boundary in the Czech Republic. The site is also a fossil locality, and the protected area is managed by AOPK ČR, Regional Office Central Bohemia.

The protected area lies in Prague and is managed by AOPK ČR, Regional Office Central Bohemia. Access is on foot; the geological profile is an exposed rock face, so expect uneven ground and keep to the marked routes.

The rock formations here contain fossils that scientists use as a reference point to understand geological periods from hundreds of millions of years ago. Researchers still visit this location to study how ancient oceans changed over time.