People & History
The Wolfram Language has built-in access to an extensive collection of continually updated data on people and many kinds of history. Free-form linguistics provide a convenient mechanism for accessing all available data; more common categories also have specific associated Wolfram Language functions.
(
) — request data using free-form linguistics
EntityValue — general access to values of properties for all types of entities
WikipediaData — Wikipedia material about entities and other topics
Notable People
PersonData — data on hundreds of thousands of current and historical figures
Social Media Connections
SocialMediaData — data on Facebook friends, Twitter followers, etc.
Historical Word Use
WordFrequencyData — historical usage data for words and 
-grams
Historical Naming Data
Accessible via free-form linguistics and EntityValue:
Socioeconomic History
CountryData — historical demographics, economics, etc. for all countries
CityData — historical demographics, founding dates, etc.
InflationAdjust — historical inflation adjustment
Cultural & Political History »
HistoricalPeriodData — data on notable historical periods
BuildingData ▪ MovieData ▪ UniversityData ▪ ...
Accessible via free-form linguistics and EntityValue:
"HistoricalEvent" ▪ "HistoricalSite" ▪ "HistoricalCountry"
Science & Technology History
Accessible via free-form linguistics and EntityValue:
"Invention" ▪ "MathProblem" ▪ "PhysicsProblem" ▪ "MannedSpaceMission"
Corporate & Financial History
FinancialData — extensive historical data on stocks, companies, etc.
CurrencyConvert — historical currency conversion rates
Accessible via free-form linguistics and EntityValue:
Historical Dates & Calendars
DateObject — represent and convert Gregorian, Julian, Jewish, etc. dates
Historical Weather, Astronomy, etc.
WeatherData — complete worldwide historical weather records
Sunrise ▪ Sunset ▪ SunPosition ▪ MoonPhase ▪ SolarEclipse ▪ ...
Paleontology
Accessible via free-form linguistics and EntityValue:
"GeologicalPeriod" ▪ "EarthImpact" ▪ "Dinosaur"