This trip starts in Lisbon city center. At Rua Marquês da fronteira starts a new cyclepath that passes by the New University of Lisbon, crosses over Av. Calouste Gulbenkian and ends at the Monsanto Park at Av. Gen. Correia Barreto (next to the Twin Towers building). After a short but steepy climb you are at Monsanto Park A great section of the track follows the Aqueduto das Águas Livres (Aqueduct of "Free Waters") that supplied water coming from Sintra district to Lisbon from 1748 until 1967.
One option is to cycle down from Monsanto to Belém distric and return to the city center following the cyclepath at the waterfront.