今昔之感
jīn​xī​zhī​gǎn

nostalgia

  1. 今昔 jīn​xī
    past and present
    The present and the past; yesterday and today
  2. 之 zhī particle
    [possessive]
    Connects a describing word or phrase to the noun it describes, similar to 的 de but used in formal or literary writing.
  3. 感 gǎn affixnoun
    [sense]
    (bound form) a feeling or emotion; also used as a suffix for a "sense of" something, such as a 责任感 zé​rèn​gǎn or 幽默感 yōu​mò​gǎn