Short answers, pulled from the story.
The first recorded labor strike in the United States occurred in 1786 when Philadelphia printers demanded $6 per week to oppose a wage reduction. This event predates the Communist Manifesto by almost a century and marks the earliest known instance of organized worker resistance in the nation.
British trade unions were finally legalized in 1872 after a Royal Commission on Trade Unions in 1867 agreed that the establishment of these organizations was to the advantage of both employers and employees. The Combination Act had banned trade unions and collective bargaining, subjecting workers to severe repression until the acts were repealed in 1824.
Trade union density is highest in the Nordic countries, with Denmark reaching 66.5 percent in 2018 and Sweden at 65.5 percent. The Nordic System of labor market regulation features a much more widespread network of collective agreements that covers most industries and most firms.
Academic literature shows substantial evidence that trade unions reduce economic inequality, with economist Joseph Stiglitz asserting that strong unions have helped to reduce inequality. A 2011 study drew a link between the decline in union membership since 1973 and expanding wage disparity, with Bruce Western, a professor of sociology at Harvard University, noting that these trends have continued.
The International Trade Union Confederation is the largest trade union federation in the world with approximately 309 affiliated organizations in 156 countries. It has a combined membership of 166 million and unites national federations from across the globe.