claim: The Washington Monument's height is either 554 ft or 555 ft.
evidence: Stuckenia pectinata -LRB- syn .. Stuckenia. Stuckenia. Potamogeton pectinatus -RRB- , commonly called sago pondweed or fennel pondweed , and sometimes called ribbon weed , is a cosmopolitan water plant species that grows in fresh and brackish water on all continents except Antarctica .. Antarctica. Antarctica