Question: WHAT IS THE GRAVITY DAM WITH THE MAXIMUM HYDRAULIC HEAD
Paraphrase: What gravity dam has the maximum hydraulic head?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q3497167 . ?ent wdt:P4441 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: Grand Coulee Dam, Three Gorges Dam, Solbergfoss power station