Monterey and Carmel both are very good places to visit and enjoy at many places. Also are many things to do there so I suggest everyone at least once. Regarding the things to do or places to visit below is the list :
In Monterey :
Monterey Bay Aquarium - Sprawling marine life attraction
Fisherman's Wharf, Monterey, California - Fishing, seafood, harbor, whale watching, walking
Cannery Row - Wine, shopping, walking
Mazda Raceway Laguna Seca - Auto & motorcycle racing
Monterey Old Town Historic District - Iconic historic homes & landmarks
Pinnacles National Park - Park featuring caves & rock formations
Colton Hall - A Museum
Cathedral of San Carlos Borromeo - Cathedral, chapel
Monterey Museum of Art - Art gallery, museum
Larkin House - History, garden
Lake El Estero - Fishing
Fort Ord Dunes State Park - Park with ocean beach & bluff-top views
Museum of Monterey - Art exhibits & local maritime history
Presidio of Monterey, California - Outdoor recreation
In Carmel :
Point Lobos - Coastal hikes, diving & a whaling museum
Mission San Carlos Borroméo del río Carmelo - Historic 18th-century church & museums
Monterey Bay Aquarium - Sprawling marine life attraction
17-Mile Drive - Golf, canyon, beach
Carmel River State Beach - Scenic bird sanctuary with scuba diving
Tor House and Hawk Tower
Forest Theater
Garrapata State Park - Ocean views & 2 miles of beachfront
Sunset Cultural Center
Jacks Peak Park - Pine forest hikes & vista views
Asilomar State Beach