Monumental

Adjective

 * 1) in the manner of a monument.
 * 2) large, grand and imposing.  Fitting to be a monument to someone or something.
 * 3) Taking a great amount of time and effort to complete
 * "a monumental task"

Adverbs for Monumental
overwhelmingly; stupendously; massively; unbelievably; colossally; gigantically; incomparably; vastly; matchlessly; prodigiously; tremendously; inexpressibly.

Thesaurus
Atlantean, Brobdingnagian, Cyclopean, Gargantuan, Herculean, Homeric, Olympian, abject, abysmal, aerial, airy, altitudinous, amplitudinous, ascending, aspiring, astronomic, astronomical, awe-inspiring, awesome, awful, boundless, bulky, calamitous, catastrophic, classic, colossal, commemorative, cosmic, cracking, dominating, egregious, elephantine, elevated, eminent, enduring, enormous, epic, ethereal, exalted, extensive, fantastic, galactic, giant, giantlike, gigantic, glorious, grand, haughty, heroic, high, high-pitched, high-reaching, high-set, high-up, historic, huge, immeasurable, immense, impressive, infinite, jumbo, king-size, large, lasting, lofty, magnificent, mammoth, marmoreal, massive, massy, memorable, memorial, mighty, monster, monstrous, mortal, mountainous, mounting, notable, noteworthy, outsize, outstanding, outtopping, overgrown, overlooking, overtopping, overwhelming, permanent, prodigious, profound, prominent, sculptitory, sculptural, sculpturesque, significant, sizable, soaring, spacious, spectacular, spiring, staggering, statuary, statuelike, statuesque, steep, striking, stupendous, sublime, superlative, supernal, terrible, titanic, topless, toplofty, topping, towering, towery, tremendous, unbelievable, unforgettable, unforgivable, uplifted, upreared, vast, voluminous, weighty, whopping, wonderful, wondrous