Final answer:
Bern is Switzerland's fifth largest city and serves as its de facto capital, hosting the national government in its federal city.
Step-by-step explanation:
The city that acts as Switzerland's de facto capital and also its fifth largest city is Bern. Despite the country's small size, Switzerland's importance on the global stage is significant due to its political neutrality and the presence of various international organizations, including the United Nations European offices, the Red Cross, and others.
Switzerland's banking and financial markets are globally recognized, with Swiss banks benefiting greatly from the nation's neutral political stance. Switzerland's culture of multilingualism reflects its diverse population, with German, French, Italian, and Romansh being the official languages across its 26 cantons.
Additionally, Switzerland is renowned for its contributions to sports, science, and education, with the Federal Institute of Technology in Zürich being a notable institution for producing Nobel Prize winners.
Bern, as the federal city, hosts the national government of Switzerland, making it the de facto capital despite not holding the official title.