1. Palazzo Altemps is a historic palace located in Rome, Italy. It was built in the 15th century for the Riario family and was later purchased by Cardinal Marco Sittico Altemps in the 16th century. The palace is known for its impressive collection of ancient art, including sculptures and mosaics from the Roman Empire. One of the most famous pieces in the collection is the Ludovisi Battle sarcophagus, which depicts a battle scene between Romans and Goths. The palace also features several ornate rooms with frescoes and decorative ceilings.

2. Palazzo Altemps is open to visitors from Tuesday to Sunday, from 9:00am to 7:45pm. The palace is closed on Mondays, as well as on January 1, May 1, and December 25. The phone number for Palazzo Altemps is +39 06 3996 7700.

3. Admission to Palazzo Altemps is included in the combined ticket for the National Roman Museum, which costs €15 for adults and €2 for EU citizens between 18 and 25 years old. Admission is free for EU citizens under 18 and over 65 years old. The palace is located in the historic center of Rome, within walking distance of many other attractions. The nearest metro station is Spagna, and several bus lines also stop nearby.