The following are acts of hajj except

The acts of Hajj are the rituals that Muslims perform as part of the pilgrimage to Mecca, and each of them has specific significance and requirements. In the list you've provided, three of the terms directly relate to the rituals of Hajj, while one stands out as not being an act of Hajj.

Tawaf is a key ritual in Hajj, which involves circumambulating the Kaaba seven times in a counter-clockwise direction. It symbolizes the unity of the believers in the worship of the One God, moving around the central point of their faith.

Ihram is the sacred state that a pilgrim must enter before performing the rites of Hajj. It involves wearing specific garments and abstaining from certain actions such as cutting hair or nails, engaging in marital relations, and hunting, as a means to prepare spiritually for the pilgrimage.

Talbiyyah is a devotional phrase repeatedly uttered by pilgrims as they proceed with the rituals of Hajj. It reflects the pilgrim's intention and readiness to perform Hajj, declaring their servitude to Allah and reinforcing their spiritual commitment.

Ziyarah generally refers to visiting holy sites and is not specific to the rituals of Hajj. While visiting places such as the Prophet's Mosque in Medina is recommended, it is not a formal part of the Hajj pilgrimage, hence it is not an act of Hajj.