There are apparently two possible sites for a Soo Opera House.

...the boom times in the eighties brought out the old Opera House on Arlington Street, which did an excellent business under the management of Mr. Percy Jordan up to the time of its destruction by fire in 1917.

The Grand Opera House was constructed in 1886-87 on Court Street, by outside capital. This structure was afterward remodeled and enlarged and is now the First Baptist Church building.

The Soo Locks (sometimes spelled Sault Locks but pronounced "soo") are a set of parallel locks, operated and maintained by the United States Army Corps of Engineers, Detroit District, that enable ships to travel between Lake Superior and the lower Great Lakes. They are located on the St. Marys River between Lake Superior and Lake Huron, between the Upper Peninsula of the U.S. state of Michigan and the Canadian province of Ontario. They bypass the rapids of the river, where the water falls 21 ft (6.4 m).

The Taungurung people are the traditional owners and inhabitants of the area Seymour now occupies. Specifically, it is the land of the Buthera Balug clan who occupied the area when Europeans first settled the region in the early 1800s. 

Formerly located at the southwest corner of Logan Avenue and Stanley Street in Winnipeg, this building was designed by local architects Walter Chesterton and McNichol and built in 1882. It had six retail spaces on the main floor, five along Logan and one along Stanley, while a lecture hall was on the second floor. The space was occupied initially by the St. Andrew’s Presbyterian Church. The building was demolished in 1923.

Manitoba Historical Society Archives

The Hotel [zum] Schwan was a famous hotel in Frankfurt am Main . It existed from 1592 to 1919. Its building, dating from 1791 on Steinweg , was destroyed by aerial bombs during the 1944 air raids on Frankfurt am Main . A cinema later stood in its place, and today it houses the Hugendubel bookstore . 

Especially in the 19th century, the Schwan was a luxury hotel of European renown. It held particular historical significance as the site of the signing of the Treaty of Frankfurt , which ended the Franco-Prussian War on May 10, 1871 .

It opened in 1885 and was a Gothic building designed by James J. Egan. It was funded by a millionaire gold and silver miner named Dennis Ryan. The building was demolished in 1962 for a surface parking lot. An office tower was built on the site circa 1980.

The Negro Traveler’s Green Book

Rosli Hotel – The Rosli Hotel was located on Bridge Street at Cataract Avenue, between the Elgin House and Windsor Hotel. It was built in 1856 by Gaspard Rosli, who came to Canada from Switzerland in 1855. The hotel was destroyed by fire in 1869 and rebuilt; this structure is sometimes referred to as the "New Rosli." With its 21 rooms, the Rosli Hotel was considered to be the "coziest and most homelike hotel in Niagara Falls." It was called the Rosli Hotel until 1928, after which point it was known as the McAllister Hotel (after the then owner, W. C.

Inter Ocean, October 4, 1885
HOTEL RICHELIEU.
“America’s Finest European Hotel” Such is the Unhesitating Verdict of All.

....

In 1885, Robert Rennert founded the enormous Rennert hotel which boasted six stories and 150 personal rooms. Inside, Rennert filled the hotel with elaborate decoration adding everything from marble and fresco, to the use of Edison’s electricity. The construction of the Rennert Hotel filled Baltimore city officials with hope and pride; through the opening of the hotel, Rennert sought to promote the growth of the city.

57 acres between 15th and 17th – Grand & Orleans Avenue.  River vista, outdoor entertainment pavilion, picnic shelters, picnic areas, playground equipment, flower garden, tennis court, basketball court, kiddie play area, reflection pond, disc golf course, restrooms.

City of Keokuk