This is one of the most interesting churches in Budapest.
The church ceiling is ornate, with lots of details.
here is an introduction of its architecture in Wikipedia:
The church is named after Saint Stephen I of Hungary, the first King of Hungary (c. 975–1038), whose “incorruptible” right hand is said to be housed in the reliquary.
This is the most important church building in Hungary, one of the most significant tourist attractions and the third highest church in Hungary.
Equal with the Hungarian Parliament Bulding, it is one of the two tallest buildings in Budapest at 96 metres (315 ft) – this equation symbolises that worldly and spiritual thinking have the same importance. According to current regulations there cannot be taller building in Budapest than 96 metres (315 ft). It has a width of 55 metres (180 ft), and length of 87.4 metres (287 ft). It was completed in 1905 after 54 years of construction, according to the plans of Miklos Ybl, and was completed by József Kauser. Much of this delay can be attributed to the collapse of the dome in 1868 which required complete demolition of the completed works and rebuilding from the ground up.
The architectural style is Neo-Classical; it has a Greek cross ground plan. The facade is anchored by two large bell towers. In the southern tower is Hungary’s biggest bell, weighing over 9 tonnes (8.9 long tons; 9.9 short tons). Its predecessor had a weight of almost 8 tonnes (7.9 long tons; 8.8 short tons), but it was used for military purposes during World War II. Visitors may access the dome by elevators or by climbing 364 stairs for a 360° view overlooking Budapest.
At first, the building was supposed to be named after Saint Leopold, the patron saint of Austria, but the plan was changed in the very last minute, so it became St. Stephen’s Basilica.