Answer
**Answer: Walkover.** Halimah's election as Singapore's first female President in 2017 was unique in that it was a walkover, where no other candidates met the eligibility criteria to contest in the election. The walkover was due to the stringent criteria set for presidential candidates, which include having held high office or having distinguished themselves in the private sector. Halimah's uncontested victory marked a significant milestone in Singapore's political history.