Next to Turin's Royal Palace, you'll find (not surprisingly) a royal church – the Royal Church of San Lorenzo, to be exact. Construction on the church was completed in 1687, and it was consecrated in 1680. The Royal Church of San Lorenzo (Real Chiesa di San Lorenzo in Italian) was built around an older structure, a former chapel for the Dukes of Savoy, which you can see near the entrance of the current church.
Designed by Modena master-architect Guarino Guarini – who was also a priest – in the 1660s, the church is located to the left of the entrance gates of the Palazzo Reale, its plain, pastel-hued façade topped by a lacy dome and hiding a frothy interior.
This fanciful Baroque jewel is smothered in oil paintings, exquisite wooden carving, gilt and multi-colored marble, with an ornate octagonal layout and eight wildly elaborate side chapels covered in seraphim and gilding. The central cupola is decorated with a six-point star, which was the signature flourish of the architect Guarini, and seems to dance as beams of sunlight pours through its windows. Its high altar is one of the most extravagant in Italy, fronted with an inlaid marble floor, studded with gilt and adorned with twisted marble columns and cherubs as well as statues of the ruling Savoy family; this is all backed by a portrait of San Lorenzo (St Lawrence in English), the patron saint of Turin.
The Royal Church of San Lorenzo is located near the entry gates of the Royal Palace, just off the Piazza Castello. It's open for visitors Monday-Friday from 7:30am-12pm and 4-7pm. On weekends, it is open from 9am-1pm and from 3-7:30pm. Admission is free. Much of Turin’s Baroque heart is pedestrianized and it is easy to walk to all the main sights. Alternatively, take trams 4, 13, 15 or 18 to Piazza Castello.