Saint Lucia's Day, observed on Dec. 13, commemorates Lucia of Syracuse, a Christian martyr associated with light. Celebrated in Scandinavia, Italy, and beyond, it symbolizes hope during winter’s darkness. In Prague, Troja Castle pays tribute with a light show on Dec. 13-14 from 5 p.m. to 11 p.m. The event features video mapping by Ondřej Rakušan, David Böhm, and Jiří Franta, accompanied by music from Aid Kid. In addition, the underground gallery will showcase other light installations from the GHMP collections. Admission is free.