1. Sacsayhuaman (Saqsaywaman) is an ancient Inca fortress located on a hill overlooking the city of Cusco in Peru. It is believed to have been built during the 15th century by the Inca Emperor Pachacuti as a ceremonial or defensive site.

The fortress is made up of three enormous walls made of massive stones that weigh up to 200 tons each. The stones were carefully cut and fitted together without the use of mortar, using the traditional Inca building technique called ashlar.

One interesting fact about Sacsayhuaman is that it is believed to have been the site of a major battle between the Inca and the Spanish during the Conquest of Peru in the 16th century.

The site is also known for its impressive acoustics, with many visitors being able to hear echoes of their own voice when standing in certain places within the fortress.

2. Sacsayhuaman is open daily from 7:00 am to 6:00 pm. Unfortunately, there is no phone number available for the site.

3. Tickets to Sacsayhuaman can be purchased at the entrance gate on the day of the visit or online in advance. The cost for a general admission ticket is 70 PEN (approx. $21 USD) for foreign visitors and 40 PEN (approx. $12 USD) for Peruvian citizens. Visitors can reach the site by taking a taxi, bus, or walking from the city of Cusco, which is located about two kilometers away.