UnScramble this Word: e s t b t o l?

Questions

In 1987 Iceberg twice the size of ---------- Island sighted in Antarctic. ?

In 1844 Spain grants Dominican Rep---------- . ?

In 1917 ---------- revolution begins. ?

In 1952 US explodes world's first ---------- bomb at Eniwetok Atoll. ?

In 1984 Pres ---------- was elected to a second term, winning 49 states. ?