Gazing at Haram is one of the arrows of Shaytan, a cause of sickness in the heart and the occurrence of immoral actions which leads a person to punishment in both worlds.
“And come not near to unlawful sex. Verily, it is a Fahishah (i.e. anything that transgresses its limits: a great sin, and an evil way that leads one to Hell unless Allah Forgives him)” [al-Isra 17:32]
Abu Hurairah RA narrates that the Prophet PBUH said, “Allah has written the very portion of zina which a man may indulge in. There will be no escape from it. The zina of the eye is the lustful look, the zina of the ears is the listening, the zina of the tongue is the speech, the zina of the hand is the grip, the zina of the feet is the walking (to the place to commit zina), the heart yearns and desires and the private parts approve all that or disprove it.” (Sahih Bukhari)
Control your gaze, guard your chastity which is purer for the believers in both worlds.
“Allah knows the fraud of the eyes, and all that the breasts conceal.” [Ghafir 40:19]”