Several insurance companies also had offices in the city. The Crystal Palace Barracks, built in 1861, an octagonal brick building with eight doors and forty-eight windows, was used for events such the Provincial Agricultural Fair of Canada West held in London that year. It was visited by Prince Arthur, Duke of Connaught and Strathearn, Governor-General John Young, 1st Baron Lisgar and Prime Minister Sir John A. Macdonald. Long before the Royal Military College of Canada was established in 1876, there were proposals for military colleges in Canada. Staffed by British Regulars, adult male students underwent three-month-long military courses from 1865 at the School of Military Instruction in London. Established by Militia General Order in 1865, the school enabled Officers of Militia or Candidates for Commission or promotion in the Militia to learn Military duties, drill and discipline, to command a Company at Battalion Drill, to Drill a Company at Company Drill, the internal economy of a Company and the duties of a Company's Officer. The school was not retained at Confederation, in 1867. In 1875, London's first iron bridge, the Blackfriars Street Bridge, was constructed. It replaced a succession of flood-failed wooden structures that had provided the city's only northern road crossing of the river. A rare example of a wrought iron bowstring arch through truss bridge, the Blackfriars remains open to pedestrian and bicycle traffic, though it was temporarily closed indefinitely to vehicular traffic due to various structural problems and was once again reopened to vehicular traffic December 1, 2018, see Blackfriars Bridge Grand Opening. The Blackfriars, amidst the river-distance between the Carling Brewery and the historic Tecumseh Park (including a major mill), linked London with its western suburb of Petersville, named for Squire Peters of Grosvenor Lodge. That community joined with the southern subdivision of Kensington in 1874, formally incorporating as the municipality of Petersville. Although it changed its name in 1880 to the more inclusive "London West", it remained a separate municipality until ratepayers voted for amalgamation with London in 1897, largely due to repeated flooding. The most serious flood was in July 1883, which resulted in serious loss of life and property devaluation. This area retains much original and attractively maintained 19th-century tradespeople's and workers' housing, including Georgian cottages as well as larger houses, and a distinct sense of place. London's eastern suburb, London East, was (and remains) an industrial centre, which also incorporated in 1874.