Learn French: Cette attraction est tellement palpitante que nous avons peur ! - This attraction is so thrilling that we are afraid!

It translates to 'so... that' to show intensity and its consequence. Here, it surrounds the adjective palpitante to mean 'so thrilling'. You could also use si instead of tellement (si palpitante que...) with the exact same meaning.

Does attraction mean the same thing here as it does in English?

While it can mean a general attraction, in French une attraction very commonly refers specifically to an amusement park ride, like a roller coaster! This explains why it is 'thrilling' and makes the speakers 'afraid'.

Why can't I say très palpitante que instead?

If you just want to say 'very thrilling,' you use très. However, because this sentence links that intensity to a specific result (que nous avons peur), you must use tellement or si. You cannot use très with que to show a consequence.

Why does the adjective palpitante end in an 'e'?

It describes cette attraction, which is a feminine noun. Adjectives must agree in gender and number with the noun they modify, so we add an 'e' to the default masculine form palpitant.