Examples of websites using
Helvetica
(Helvetica is a sans serif font designed by Max Miedinger, Linotype Design Studio, and released by Linotype in 1957. It is available in a wide range of styles and weights)
with
Helvetica Neue
(Helvetica Neue is a popular Sans Serif font designed by Max Miedinger and published through Linotype in 1961. The font family consists of multiple styles with different weights and matching italics)