such .asNo other holiday that is today widely celebrated in

such...as...：固定词组,像...这样的,诸如
例：铜和铝是具有良好导电性的金属.
Such metals as copper and aluminum have a good electrical conductivity.
或
Metals such as copper and aluminum have a good electrical conductivity.
两处such...as...是相同的用法
such + adj + n,如That is such a funny book.,此处的such则是重在强调这是一本有趣的书,并不是“例举”的意思.
你的例句中,such...as...显然是“例如”的意思,如果such用于形容历史悠久,那么后面就不跟as,而用like代替,如：No other holiday that is today widely celebrated in North America has such a long history like Thanksgiving.

such a long history的意思和so long history的意思是一样的
such一定要配a+noun(long history为一个名词,意"悠久历史")
整句是"这么的一个悠久历史的"
as是像....一样
所以是"像感恩节一样这么悠久历史的"

such...as像。。。一样
as后为thanksgiving,构不成一个完整的句子。即缺少成分。故只能用as 引导
而如果本句中history后是一个完整的句子，则用that