`` Jeopardy ! '' host Alex Trebek serves as parade 's grand marshal . The event is the culmination of a year in which more than 100 million people tuned into the popular game show on television. National Cherry Blossom Festival marks the arrival of spring .
`` Jeopardy ! '' host Alex Trebek serves as parade 's grand marshal . Cherry blossom trees were a gift to U.S. government from Japan in 1912 . National Cherry Blossom Festival marks the arrival of spring .