We recommend visiting the Old City Center in Valencia.
Some suggestions:
The Cathedral & Plaza de la Virgen
Santa Catalina Tower & Plaza de la Reina: While here, you can try Horchata, a traditional non-alcoholic drink made of tiger nuts. We recommend Horchatería Daniel or Santa Catalina.
Barrio del Carmen: Take in the sights of the old city and explore its charm.
The Silk Exchange (La Lonja)
The Central Market is a great place to check out local food and specialties. It is open everyday from 7:30 am to 3:00 pm (except on Sundays).
The City of Arts and Sciences is located in Valencia's old riverbank, it is designed by local architect Santiago Calatrava. It hosts multiple venues, including a science museum, opera house, aquarium, etc.
Paella is the traditional dish from Valencia, with many different varieties available (paella Valenciana, arroz a banda, arroz del senyoret, arroz negro, etc.). Here's a few restaurants we recommend: Alqueria del Brosquil, Alqueria del Pou, and Casa Carmela. There are also many traditional restaurants in el Palmar, a small town located next to the Albufera Natural Park, just outside the city.
As a coastal city, Valencia hosts multiple beaches (Malvarrosa, Patacona, El Saler, etc.).