Antibiotics revolutionized medicine in the 20th century, and have together with vaccination led to the near eradication of diseases such as tuberculosis in the developed world. Their effectiveness and easy access led to overuse, especially in livestock raising, prompting bacteria to develop resistance. This has led to widespread problems with antimicrobial and antibiotic resistance, so much as to prompt the World Health Organization to classify antimicrobial resistance as a "serious threat [that] is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country".
What organization called antimicrobial resistance a 'serious threat?'
World Health Organization

In 1836, at a party hosted by Marie d'Agoult, Chopin met the French author George Sand (born [Amantine] Aurore [Lucile] Dupin). Short (under five feet, or 152 cm), dark, big-eyed and a cigar smoker, she initially repelled Chopin, who remarked, "What an unattractive person la Sand is. Is she really a woman?" However, by early 1837 Maria Wodzińska's mother had made it clear to Chopin in correspondence that a marriage with her daughter was unlikely to proceed. It is thought that she was influenced by his poor health and possibly also by rumours about his associations with women such as d'Agoult and Sand. Chopin finally placed the letters from Maria and her mother in a package on which he wrote, in Polish, "My tragedy". Sand, in a letter to Grzymała of June 1838, admitted strong feelings for the composer and debated whether to abandon a current affair in order to begin a relationship with Chopin; she asked Grzymała to assess Chopin's relationship with Maria Wodzińska, without realising that the affair, at least from Maria's side, was over.
What was a possible reason for Chopin's failed engagement to Maria Wodzińska?
his poor health

Juscelino Kubitschek, President of Brazil from 1956 to 1961, ordered the construction of Brasília, fulfilling the promise of the Constitution and his own political campaign promise. Building Brasília was part of Juscelino's "fifty years of prosperity in five" plan. Lúcio Costa won a contest and was the main urban planner in 1957, with 5550 people competing. Oscar Niemeyer, a close friend, was the chief architect of most public buildings and Roberto Burle Marx was the landscape designer. Brasília was built in 41 months, from 1956 to April 21, 1960, when it was officially inaugurated.
When did Kubitschek become President of Brazil?
1956