The Church of the Nativity of the Virgin Mary in Jablonné v Podještědí is a historically significant monument. It evolved from a sacred Gothic church into an observation tower. Located on Školní Street near Míru Square, this structure showcases elements of both Gothic and Baroque architecture. It stands as a testament to its rich history and architectural transformation over the centuries. As a cultural monument listed in the Central List of Cultural Monuments of the Czech Republic, it holds notable value for its preserved architectural features.

The origins of the Church date back to the mid-13th century when Havel z Lemberka established a Dominican monastery and parish church in Jablonné v Podještědí. The first documented mention of the church appears in texts from 1279–1290 by Bishop Tobiasz z Bechyně, highlighting its early significance within the region. By 1352, it was recorded as a deanery church in the papal tithes register. In the late 13th century, Zdislav z Lemberka transferred patronage rights to the Cistercian Abbey in Hradiště nad Jizerou, which maintained them until 1378.

Architecturally, the church was initially constructed at the southeastern city wall with a rectangular nave measuring 25.4 meters by 16.4 meters. The original structure featured rubble stone walls bound with lime mortar and included window openings on both sides of its façade. Over time, it underwent significant transformations, including Gothic renovations that are difficult to date precisely but suggest influences from the transition between Romanesque and Gothic styles. By the mid-15th century, following damage during the Hussite Wars, the church was reconstructed in 1457 and rededicated to the Nativity of the Virgin Mary.

Ownership and administration of the church saw several changes over time. After the Cistercians, it came under the control of František Josef Pachta z Rájova in 1786, who reported repairs and construction of a new tower. The Baroque reconstruction from 1781 to 1783, led by architect Filip Heger, introduced significant changes including a new west façade and a seven-story tower that remains a prominent feature today.

Key events in the church's history include its damage during the Hussite Wars between 1425 and 1426. Despite these challenges, it was restored and continued to serve as a place of worship until the late 18th century when it underwent further transformations. In 1788, a devastating fire led to its decline, and by 1863, it had been repurposed into an observation tower after serving briefly as a brewery.

Today, the Church of the Nativity of the Virgin Mary stands as an intriguing blend of architectural styles and historical narratives. Visitors can appreciate its preserved Gothic elements alongside Baroque modifications, making it a worthwhile destination for those interested in cultural heritage and architecture. Its transformation over time reflects the dynamic history of Jablonné v Podještědí and invites exploration into the layers of stories embedded within its walls.