Rio de Janeiro was chosen to host the III Pan-American Conference, the most significant diplomatic gathering in the Americas and the first to be held in South America. Between July 21 and August 27 of that year, representatives from 19 countries convened at the Monroe Palace to discuss the future of the American continent.

It marked the first instance in history that a U.S. Secretary of State participated in an official event abroad. Originally named the São Luiz Palace and inaugurated as the conference venue, it was later renamed in honor of U.S. President James Monroe, a proponent of regional solidarity. The building, originally constructed to represent Brazil at the Saint Louis World's Fair, received the World Architecture Prize in 1904.

The first major exhibition held in the country, the Commemorative National Exhibition of the 1st Centennial of the Opening of Brazil's Ports took place in the Urca neighborhood from August 11 to November 15, 1908. The event featured over 30 structures, including representative pavilions of Brazilian states, a cinema, two theaters, a botanical garden, a skating rink, and the Portugal Pavilion. The exhibition showcased numerous innovations in the fields of arts, science, commerce, industry, and agriculture to the visitors.

During the event, inspired by the spirit of modernity, engineer Augusto Ferreira Ramos conceived the idea of building one of the symbols of the country and the city of Rio: the Sugarloaf Cable Car.

The first major universal exhibition in the post-war period, the Commemorative International Exhibition of the Centennial of Independence brought representatives from 14 countries and all states of the federation to the then federal capital. Serving as a true showcase of progress, exhibitors presented visitors with the latest advancements in various fields of knowledge, including agriculture, industry, and sciences.

Held between September 7, 1922, and July 24, 1923, the monumental exhibition left the city of Rio with four historic buildings: the Pavilion of Administration and the Federal District (now the headquarters of the Museum of Image and Sound), the Statistics Pavilions (currently the Cultural Center of the Ministry of Health), the Palace of Great Industries (part of today's National Historical Museum), and the Palace of France, a replica of the Petit Trianon of Versailles, donated in 1923 to the Brazilian Academy of Letters. Iconic postcards of Rio and the country, the Gloria Hotel (1922) and Copacabana Palace (1923) were initially planned to accommodate visitors to the Exhibition.

Held annually between 1928 and 1940, the International Sample Fair was Brazil's most important business forum. In the spirit of major fairs and exhibitions in the world's leading capitals, Rio was chosen to host entrepreneurs, unions, and international representatives from various countries.

Open to the general public, the fair combined product exhibitions, business spaces, and artistic and cultural performances. Interrupted with the advent of World War II, the event left a lasting impact. It is estimated that over 700 companies and one million people attended the fair.

Between January 15 and 28, 1942, chancellors from across the American continent gathered at the Rio Conference to deliberate on the position of the countries during World War II. Convened by the United States shortly after the Japanese attack on Pearl Harbor, the Third Meeting of Consultation of the American Republics' Chancellors produced over 40 resolutions, including the unanimous approval for the immediate severance of diplomatic and commercial relations with all Axis countries.

A crucial turning point in Brazilian diplomatic history, at the end of the conference, Brazil severed relations with Germany, Italy, and Japan. Six months later, after successive attacks by German and Italian submarines on Brazilian ships, the country declared war on the Axis powers.

With the end of World War II and the onset of the Cold War, the American states gathered in Rio between August and September 1947 to discuss the creation of a continental security system. Signed on September 2 of that year, the Pact or Rio Treaty established the norms of collective defense that remain in effect to this day.

Officially titled the Inter-American Treaty of Reciprocal Assistance (TIAR), it outlines measures of legitimate defense and joint actions to be taken by all signatory countries in the event of an attack on any member state of the alliance.

As the main host city for the 1950 World Cup, the first after World War II, Rio de Janeiro hosted 8 matches, including 4 featuring the Brazilian National Team, as well as the championship final held at the Municipal Stadium of Rio de Janeiro, the Maracanã.

Built in record time to host the event, the 'largest in the world' had a capacity for 200 thousand people, equivalent to 10% of the population of Rio de Janeiro in 1950. Home to the largest crowds in the history of sports, the stadium became the home of the Brazilian national team. It was on its grounds that Edson Arantes do Nascimento, the King Pelé, scored his thousandth goal.

Rio de Janeiro became the global capital of Catholicism in 1955. It is estimated that over a million believers from all corners of the globe attended the 36th International Eucharistic Congress, held in July of that year at Aterro do Flamengo.

Contested by countries worldwide, the gathering inspired the implementation of projects that would leave a lasting legacy for the city, such as the expansion of the Guandu River aqueduct and the landfilling of part of the Flamengo neighborhood.

Held at the Museum of Modern Art in Rio de Janeiro, the 22nd Joint Meeting of the World Bank and the International Monetary Fund brought more than 3,000 participants from 108 member countries to the Marvelous City. In Rio, the most important event in the world economy innovated by creating Special Drawing Rights, a kind of international reserve currency still in operation today.

Interestingly, the very idea of creating the IMF has its origins in Rio de Janeiro. The final declaration of the III Meeting of Consultation of the American Republics, held 25 years earlier in the city, recommended the creation of an International Stabilization Fund, a measure realized in 1944.

The largest international event in history up to that point, the United Nations Conference on Environment and Development brought 108 heads of state and representatives from 178 nations to Rio de Janeiro. Held at Riocentro, the countries approved international agreements that still guide international environmental policy today, the so-called UN framework conventions: for climate, for the conservation of biodiversity, and for combating desertification. The event solidified the concept of sustainable development and firmly placed the issue of climate change on the global agenda.

From June 28 to 29, Rio hosted the first summit meeting of Latin America, the Caribbean, and the European Union. Held at the Museum of Modern Art, 15 heads of state and representatives from 48 countries established a Bi-regional Strategic Partnership, in effect to this day.

Among the 69 points in the final declaration, notable themes include trade and regional integration, democracy and human rights, combating poverty and social promotion, climate change, and sustainable development.

In total, 42 countries, 5,633 athletes, and over 20,000 volunteers made the XV Pan American Games the largest in history up to that point. Two weeks later, the city would host the Parapan American Games, with around 1,300 athletes from 26 countries in the continent participating. A third event would forever mark the Golden Year of the Marvelous City: after two years of elections, Christ the Redeemer became one of the Seven Wonders of the World.

Twenty years after Rio-92, representatives from 188 countries gathered in Rio de Janeiro from June 13 to 22 to renew political commitment to sustainable development and poverty eradication.

In total, 487 ministers and 105 heads of state and government were present at the Conference, whose final declaration was adopted by consensus. Rio+20 succeeded in facilitating integration between civil society and the multilateral process. It is estimated that more than 60,000 people participated in virtual and in-person discussions at the event.

From July 23 to 28, Rio once again became the global capital of the Catholic faith. Presided over by the first Latin American Pope, the XXVIII World Youth Day was Pope Francis's first encounter with Catholic youth and also the first international event for the new pontiff.

The event, whose tourist influx was the largest in Brazil's history up to that point, brought millions of faithful from all over the world to the city. On the sands of Copacabana, an estimated 3.7 million pilgrims attended the closing Mass in person, making it the largest Mass.

As one of the venues for the twentieth edition of the World Cup, Rio de Janeiro hosted seven matches of the most important football spectacle on the planet. Held between June 12 and July 13, 2014, the event returned to Brazil after six decades of anticipation. The Maracanã, once again, would be the stage for the grand final. Throughout history, only two stadiums have hosted two World Cup finals: the Azteca Stadium in Mexico City and the Maracanã, aptly known as the Temple of Football.

The Museum of Tomorrow was the venue for the First C40 Sustainable Cities Finance Forum, an important global network composed of around 100 mayors from major cities around the world. From April 5 to 7, 2016, global leaders in urban finance gathered in Rio de Janeiro to promote the financing of climate action in cities. The event, a pioneering initiative to connect cities and the financial sector, brought together more than 130 representatives from government, non-governmental organizations, and financial institutions.

From August 5 to 21, Rio became the first Olympic city in South America. Thirty-four competition venues, concentrated in four areas - Barra, Copacabana, Deodoro, and Maracanã - welcomed 11,000 athletes, 45 delegations of heads of state, and more than 30,000 journalists from all corners. The Olympic Boulevard, in the revitalized port area of Rio, became the main center for gatherings and celebrations for the over 500,000 people who came to the city during that period. It is estimated that the competitions reached about 5 billion viewers worldwide. From September 7 to 18, it was time for the Paralympic dream: about 4,500 athletes from 176 countries shone in 22 sports.

Rio hosted the foreign ministers of Brazil, Russia, India, China, and South Africa for the III Meeting of BRICS Foreign Ministers. The meeting took place at the historic Itamaraty Palace, the headquarters of the Ministry of Foreign Affairs of Brazil from 1899 until its relocation to Brasília in 1970. During the meeting, the ministers discussed important topics on the international agenda, such as global governance reform and multilateral cooperation among the countries.

Several initiatives are solidifying the city of Rio as an international reference in innovation and technology, such as the creation of Porto Maravalley - a technological hub located in the port region that brings together startups, investors, large companies, and universities - and the hosting of Web Summit, one of the largest and most important technology fairs in the world..

Held at Riocentro from May 1 to 4, 2023, the event welcomed more than 21,000 people and companies from various sectors of the technology industry. On the agenda were cutting-edge topics such as artificial intelligence, fintechs, and cryptocurrencies. Historically predisposed to innovation, from April 15 to 18, 2024, Rio will once again host an edition of the event.

Rio will be the capital of the world in 2024. Chosen as the venue for the G20 summit, the city will host the group composed of the 19 largest economies in the world and the European Union. Responsible for 85% of the GDP and over 75% of global trade, the world's top leaders will discuss the future of global governance and sustainable development in Rio. It is estimated that more than 100 other events will be organized throughout the year by engagement groups, startups, think tanks, and universities.