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 table_name_36 ( country VARCHAR, year_opened VARCHAR, span_feet VARCHAR, material VARCHAR, span_metres VARCHAR )

### Question ###
Which country's material was concrete when the span metres were less than 270, span feet is more than 837, and the year opened was 1943?

### Accurate SQL ###

SELECT country FROM table_name_36 WHERE material = "concrete" AND span_metres < 270 AND span_feet > 837 AND year_opened = "1943"