Extreme intensity (tan / tanto que)

"So... that" with adjectives

To connect an intense situation to its direct result, use the structure tan + adjective (or adverb) + que ("so [adjective] that...").

What a market! It is so full that we cannot walk.
¡Qué mercado! Está tan lleno que no podemos caminar.
The market is so packed that I cannot leave.
El mercado está tan apretado que no puedo salir.

"So much / so many... that" with nouns

When the intensity involves a noun rather than an adjective, use tanto instead of tan. It must agree in gender and number with the noun it describes (tanto, tanta, tantos, tantas).

There is so much commotion in the market that we walk squeezed together.
Hay tanto tumulto en el mercado que caminamos apretados.
So much merchandise is sold here that the street is always busy.
Aquí se vende tanta mercancía que la calle siempre está ocupada.

Notice how tantas agrees with the feminine plural noun carretillas (handcarts):

The sellers bring so many handcarts that they crash into the people.
Los vendedores traen tantas carretillas que chocan con la gente.