CREATE TABLE table_name_36 (country VARCHAR(255), year_opened VARCHAR(255), span_feet VARCHAR(255), material VARCHAR(255), span_metres VARCHAR(255))
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?
    
SQL: SELECT country FROM table_name_36 WHERE material = "concrete" AND span_metres < 270 AND span_feet > 837 AND year_opened = "1943"