Give the height of the tallest athlete from Portugal.
the tallest athlete refers to id where MAX(height); from Portugal refers to region_name = 'Portugal';
SELECT T3.height FROM noc_region AS T1 INNER JOIN person_region AS T2 ON T1.id = T2.region_id INNER JOIN person AS T3 ON T2.person_id = T3.id WHERE T1.region_name = 'Portugal' ORDER BY T3.height DESC LIMIT 1