of Kursk is incorporated as Kursk Urban Okrug. Economy and infrastructure In addition to its importance as an administrative hub, Kursk is important as an industrial centre. Activity focuses on iron based industry, the chemical sector and a large food processing industry, reflecting the richness of agriculture in the surrounding "Black Earth" region. Particularly noteworthy is the so-called Kursk Magnetic Anomaly (Russian: Курская магнитная аномалия), the world's largest known iron-ore reserve, where the iron content of the ore ranges from 35% up to 60%. In Kurchatov, some to the south-west, is the Kursk Nuclear Power Plant, incorporating four RBMK-1000 ("High Power Channel-type Reactor") (Russian: Реактор Большой Мощности Канальный) reactors similar to those implicated in the 1986 Chernobyl disaster. The oldest of the Kursk reactors has been operational since 1977, and the newest of them since 1986. Attractions The oldest building in Kursk is the upper church of the Trinity Monastery, a good example of the transition style characteristic of Peter the Great's early reign. The oldest lay building is the so-called Romodanovsky Chamber, although it was erected in all probability in the mid-18th century, when the Romodanovsky family had ceased to exist. The city cathedral was built between 1752 and 1778 in the splendid Baroque style and was decorated so sumptuously that many art historians attributed it to Bartolomeo Rastrelli. Although Rastrelli's authorship is out of the question, the cathedral is indeed the most impressive monument of Elizabethan Baroque not to be commissioned by the imperial family or built in the imperial capital. The cathedral has two stories, with the lower church consecrated to St. Sergius of Radonezh and the upper one — to the Theotokos of Kazan. The upper church is noted for an intricate icon screen which took sixteen years to complete. The three-story cathedral bell tower derives peculiar interest from the fact that Seraphim of Sarov, whose father took part in construction works, survived an accidental fall from its top floor at the age of seven. The Resurrection Church is also shown where St. Seraphim was baptized. The monastery cathedral of the Sign (1816–26) is another imposing edifice, rigorously formulated in the purest Neoclassical style, with a cupola measuring in diameter and rising high. The interior was formerly as rich as colored marbles, gilding, and frescoes could make it. During the Soviet period, the cathedral was desecrated, four lateral domes and twin belltowers over the entrance pulled