Standing tall amidst the bustling streets near Hoan Kiem Lake and the Old Quarter, St. Joseph's Cathedral (Nhà thờ Lớn Hà Nội) is a striking landmark and the oldest Roman Catholic church in Hanoi. Inaugurated in 1886 by the French colonial government, its impressive Neo-Gothic architecture presents a distinct contrast to the surrounding Vietnamese and Sino-Vietnamese structures. Often drawing comparisons to Notre Dame de Paris, the cathedral serves as the architectural centerpiece of Hanoi's Catholic community and a significant historical site.

The cathedral's exterior is characterized by its twin square bell towers reaching towards the sky, an imposing facade with arched doorways, and traditional Gothic elements. Inside (access may depend on service times, as it's an active church), visitors can admire classic features of European ecclesiastical architecture, including high vaulted ceilings creating a sense of grandeur, intricate stained-glass windows originally imported from France depicting biblical scenes, and various religious statues and altars, creating a solemn and reverent atmosphere.

Beyond its religious function, St. Joseph's Cathedral is a popular spot for tourists and locals alike, admired for its historical significance and architectural beauty, making it a frequent backdrop for photos. The area surrounding the cathedral, particularly Nha Chung Street and nearby Ly Quoc Su Street, is equally famous, known for its vibrant atmosphere with numerous trendy cafes, boutique shops, and the quintessential Hanoi experience of sitting on small stools enjoying lemon tea ('trà chanh nhà thờ'). A visit here offers both a glimpse into Hanoi's colonial past and a taste of its contemporary local culture.