Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE employment ( Company_ID int, People_ID int, Year_working int )
TABLE: CREATE TABLE company ( Company_ID real, Name text, Headquarters text, Industry text, Sales_in_Billion real, Profits_in_Billion real, Assets_in_Billion real, Market_Value_in_Billion real )
TABLE: CREATE TABLE people ( People_ID int, Age int, Name text, Nationality text, Graduation_College text )

### Question ###
What is the number of companies for each headquarter? Visualize by bar chart.

### Accurate SQL ###

SELECT Headquarters, COUNT(Headquarters) FROM company GROUP BY Headquarters